Compounds for treating huntington&#39;s disease

ABSTRACT

In particular, the present description relates to substituted monocyclic heteroaryl compounds of Formula (I), forms and pharmaceutical compositions thereof and methods of using such compounds, forms, or compositions thereof for treating or ameliorating Huntington&#39;s disease.

An aspect of the present description relates to compounds, forms, and pharmaceutical compositions thereof and methods of using such compounds, forms, or compositions thereof useful for treating or ameliorating Huntington's disease. In particular, another aspect of the present description relates to substituted monocyclic heteroaryl compounds, forms and pharmaceutical compositions thereof and methods of using such compounds, forms, or compositions thereof for treating or ameliorating Huntington's disease.

BACKGROUND

Huntington's disease (HD) is a progressive, autosomal dominant neurodegenerative disorder of the brain, having symptoms characterized by involuntary movements, cognitive impairment, and mental deterioration. Death, typically caused by pneumonia or coronary artery disease, usually occurs 13 to 15 years after the onset of symptoms. The prevalence of HD is between three and seven individuals per 100,000 in populations of western European descent. In North America, an estimated 30,000 people have HD, while an additional 200,000 people are at risk of inheriting the disease from an affected parent. The disease is caused by an expansion of uninterrupted trinucleotide CAG repeats in the “mutant” huntingtin (Htt) gene, leading to production of HTT (Htt protein) with an expanded poly-glutamine (polyQ) stretch, also known as a “CAG repeat” sequence. There are no current small molecule therapies targeting the underlying cause of the disease, leaving a high unmet need for medications that can be used for treating or ameliorating HD. Consequently, there remains a need to identify and provide small molecule compounds for treating or ameliorating HD.

All other documents referred to herein are incorporated by reference into the present application as though fully set forth herein.

SUMMARY

An aspect of the present description includes compounds comprising, a compound of Formula (I):

or a form thereof, wherein X, B, R₃, and n are as defined herein.

An aspect of the present description includes a method for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound of Formula (I) or a form thereof.

An aspect of the present description includes a method for use of a compound of Formula (I) or a form or composition thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form or composition thereof.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form thereof.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in the manufacture of a medicament for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the medicament.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in a combination product with one or more therapeutic agents for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form thereof in combination with an effective amount of the one or more agents.

DETAILED DESCRIPTION

An aspect of the present description relates to compounds comprising, a compound of Formula (I):

or a form thereof, wherein:

-   X is CHR_(1a), C═O, O, NR_(1b), or a bond; -   R_(1a) is independently selected from hydrogen, halogen, hydroxyl,     cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, and     hydroxyl-C₁₋₄alkyl; -   R_(1b) is independently selected from hydrogen, C₁₋₄alkyl,     deutero-C₁₋₄alkyl, and halo-C₁₋₄alkyl; -   B is heterocyclyl, -   wherein heterocyclyl is a saturated or partially unsaturated 3-7     membered monocyclic, 6-10 membered bicyclic or 13-16 membered     polycyclic ring system having 1, 2, or 3 heteroatom ring members     independently selected from N, O, or S, each optionally substituted     with 1, 2, 3, 4, or 5 substituents each selected from R₂; -   R₂ is independently selected from halogen, C₁₋₄alkyl,     deutero-C₁₋₄alkyl, amino, C₁₋₄alkyl-amino, and (C₁₋₄alkyl)₂-amino; -   R₃ is independently selected from halogen, hydroxyl, cyano,     C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino,     C₁₋₄alkyl-amino, (C₁₋₄alkyl)₂-amino, C₁₋₄alkoxy, halo-C₁₋₄alkoxy,     heteroaryl, heterocyclyl, and phenyl, -   wherein heteroaryl is a 3-7 membered monocyclic or 6-10 membered     bicyclic ring system having 1, 2, 3, or 4 heteroatom ring members     independently selected from N, O, or S, -   wherein heterocyclyl is a saturated or partially unsaturated 3-7     membered monocyclic, 6-10 membered bicyclic or 13-16 membered     polycyclic ring system having 1, 2, or 3 heteroatom ring members     independently selected from N, O, or S, and -   wherein each instance of phenyl, heteroaryl or heterocyclyl is     optionally substituted with 1 or 2 substituents each selected from     R₄; -   n is 1, 2 or 3; and -   R₄ is independently selected from halogen, hydroxyl, cyano,     C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino,     C₁₋₄alkyl-amino, (C₁₋₄alkyl)₂-amino, C₁₋₄alkoxy, and     halo-C₁₋₄alkoxy; -   wherein a form of the compound is selected from the group consisting     of a salt, hydrate, solvate, racemate, enantiomer, diastereomer,     stereoisomer, and tautomer form thereof.

ASPECTS OF THE DESCRIPTION

Another aspect of the present description includes a compound of Formula (I):

or a form thereof, wherein:

-   X is CHR_(1a), C═O, O, NR_(1b), or a bond; -   R_(1a) is independently selected from hydrogen, halogen, hydroxyl,     cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, and     hydroxyl-C₁₋₄alkyl; -   R_(1b) is independently selected from hydrogen, C₁₋₄alkyl,     deutero-C₁₋₄alkyl, and halo-C₁₋₄alkyl; B is heterocyclyl, -   wherein heterocyclyl is a saturated or partially unsaturated 3-7     membered monocyclic, 6-10 membered bicyclic or 13-16 membered     polycyclic ring system having 1, 2, or 3 heteroatom ring members     independently selected from N, O, or S, each optionally substituted     with 1, 2, 3, 4, or 5 substituents each selected from R₂; -   R₂ is independently selected from halogen, C₁₋₄alkyl,     deutero-C₁₋₄alkyl, amino, C₁₋₄alkyl-amino, and (C₁₋₄alkyl)₂-amino; -   R₃ is independently selected from halogen, hydroxyl, cyano,     C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino,     C₁₋₄alkyl-amino, (C₁₋₄alkyl)₂-amino, C₁₋₄alkoxy, halo-C₁₋₄alkoxy,     heteroaryl, heterocyclyl, and phenyl, -   wherein heteroaryl is a 3-7 membered monocyclic or 6-10 membered     bicyclic ring system having 1, 2, 3, or 4 heteroatom ring members     independently selected from N, O, or S, -   wherein heterocyclyl is a saturated or partially unsaturated 3-7     membered monocyclic, 6-10 membered bicyclic or 13-16 membered     polycyclic ring system having 1, 2, or 3 heteroatom ring members     independently selected from N, O, or S, and -   wherein each instance of phenyl, heteroaryl or heterocyclyl is     optionally substituted with 1 or 2 substituents each selected from     R₄; -   n is 1, 2 or 3; and -   R₄ is independently selected from halogen, hydroxyl, cyano,     C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino,     C₁₋₄alkyl-amino, (C₁₋₄alkyl)₂-amino, C₁₋₄alkoxy, and     halo-C₁₋₄alkoxy.

One aspect includes a compound of Formula (I), wherein X is selected from CHR_(1a), C═O, O, NR_(1b), and a bond.

Another aspect includes a compound of Formula (I) wherein X is CHR_(1a).

Another aspect includes a compound of Formula (I) wherein X is C═O.

Another aspect includes a compound of Formula (I) wherein X is O.

Another aspect includes a compound of Formula (I) wherein X is NR_(1b).

Another aspect includes a compound of Formula (I) wherein X is a bond.

One aspect includes a compound of Formula (I), wherein R_(1a) is selected from hydrogen, halogen, hydroxyl, cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, and hydroxyl-C₁₋₄alkyl.

Another aspect includes a compound of Formula (I), wherein R_(1a) is selected from cyano and amino.

Another aspect includes a compound of Formula (I), wherein R_(1a) is cyano.

Another aspect includes a compound of Formula (I), wherein R_(1a) is amino.

One aspect includes a compound of Formula (I), wherein R_(1b) is selected from hydrogen, C₁₋₄alkyl, deutero-C₁₋₄alkyl, and halo-C₁₋₄alkyl.

Another aspect includes a compound of Formula (I), wherein R_(1b) is selected from hydrogen and C₁₋₄alkyl.

Another aspect includes a compound of Formula (I), wherein R_(1b) is hydrogen.

Another aspect includes a compound of Formula (I), wherein R_(1b) is C₁₋₄alkyl selected from methyl, ethyl, propyl, isopropyl, butyl, and tert-butyl.

Another aspect includes a compound of Formula (I), wherein R_(1b) is methyl.

One aspect includes a compound of Formula (I), wherein B is heterocyclyl,

wherein heterocyclyl is a saturated or partially unsaturated 3-7 membered monocyclic, 6-10 membered bicyclic or 13-16 membered polycyclic ring system having 1, 2, or 3 heteroatom ring members independently selected from N, O, or S, each optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂.

Another aspect includes a compound of Formula (I), wherein B is heterocyclyl selected from azetidinyl, tetrahydrofuranyl, pyrrolidinyl, piperidinyl, piperazinyl, 1,4-diazepanyl, 1,2-dihydropyridinyl, 1,2,5,6-tetrahydropyridinyl, 1,2,3,6-tetrahydropyridinyl, hexahydrocyclopentapyrrol-(1H)-yl, hexahydropyrrolo[3,2-b]pyrrol-(2H)-yl, hexahydropyrrolo[3,4-b]pyrrol-(2H)-yl, (3aS,6aS)-hexahydropyrrolo[3,4-b]pyrrol-(2H)-yl, hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, (3aS,6aS)-hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, (3aR,6aR)-hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, (3aR,6aS)-hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, octahydro-2H-pyrrolo[3,4-c]pyridinyl, octahydro-5H-pyrrolo[3,2-c]pyridinyl, octahydro-6H-pyrrolo[3,4-b]pyridinyl, (4aR,7aR)-octahydro-6H-pyrrolo[3,4-b]pyridinyl, (4aS,7aS)-octahydro-6H-pyrrolo[3,4-b]pyridinyl, hexahydropyrrolo[1,2-a]pyrazin-(2H)-one, hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (7R,8aS)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aS)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aR)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, hexahydro-1H-cyclobuta[1.2-c:1,4-c′]dipyrrol-(3H)-yl, (8aS)-octahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aR)-octahydropyrrolo[1,2-a]pyrazin-(1H)-yl, octahydro-2H-pyrido[1,2-a]pyrazinyl, hexahydropyrrolo[3,4-b][1,4]oxazin-(2H)-yl, 5-azaspiro[2.4]heptanyl, 2-oxa-6-azaspiro[3.4]octanyl, 3-azabicyclo[3.1.0]hexanyl, 8-azabicyclo[3.2.1]octanyl, (1R,5S)-8-azabicyclo[3.2.1]octanyl, 8-azabicyclo[3.2.1]oct-2-en-yl, (1R,5S)-8-azabicyclo[3.2.1]oct-2-en-yl, 9-azabicyclo[3.3.1]nonanyl, (1R,5S)-9-azabicyclo[3.3.1]nonanyl, 2,5-diazabicyclo[2.2.1]heptanyl, (1S,4S)-2,5-diazabicyclo[2.2.1]heptanyl, 1,4-diazabicyclo[3.1.1]heptanyl, 3,6-diazabicyclo[3.2.0]heptanyl, 2,5-diazabicyclo[2.2.2]octanyl, 1,4-diazabicyclo[3.2.1]octanyl, 3,8-diazabicyclo[3.2.1]octanyl, (1R,5S)-3,8-diazabicyclo[3.2.1]octanyl, 1,4-diazabicyclo[3.2.2]nonanyl, azaspiro[3.3]heptanyl, 4,7-diazaspiro[2.5]octanyl, 2,6-diazaspiro[3.3]heptanyl, 2,6-diazaspiro[3.4]octanyl, 1,7,-diazaspiro[4.4]nonanyl, 1,7-diazaspiro[3.5]nonanyl, 2,6-diazaspiro[3.5]nonanyl, 2,7-diazaspiro[3.5]nonanyl, 5,8-diazaspiro[3.5]nonanyl, 2,7-diazaspiro[4.4]nonanyl, 2,7-diazaspiro[4.5]decanyl, 2,8-diazaspiro[4.5]decanyl, 6,9-diazaspiro[4.5]decyl, 6-oxa-2,9-diazaspiro[4.5]decanyl, 2,9-diazaspiro[5.5]undecanyl, and 7-azadispiro[5.1.5⁸.3⁶]hexadecanyl, optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂.

Another aspect includes a compound of Formula (I), wherein B is heterocyclyl selected from pyrrolidinyl, piperidinyl, hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, 8-azabicyclo[3.2.1]octanyl, 2,6-diazaspiro[3.4]octanyl, and 7-azadispiro[5.1.5⁸.3⁶]hexadecanyl, optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂.

Another aspect includes a compound of Formula (I), wherein B is heterocyclyl selected from pyrrolidinyl, piperidinyl, hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, 8-azabicyclo[3.2.1]octanyl, 2,6-diazaspiro[3.4]octanyl, and 7-azadispiro[5.1.5⁸.3⁶]hexadecanyl, optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂.

Another aspect includes a compound of Formula (I), wherein B is heterocyclyl selected from pyrrolidinyl and piperidinyl, optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂.

Another aspect includes a compound of Formula (I), wherein B is heterocyclyl selected from selected from azetidin-1-yl, tetrahydrofuran-3-yl, pyrrolidin-1-yl, pyrrolidin-3-yl, piperidin-1-yl, piperidin-3-yl, piperidin-4-yl, piperazin-1-yl, 1,4-diazepan-1-yl, 1,2-dihydropyridin-2-yl, 1,2-dihydropyridin-3-yl, 1,2-dihydropyridin-4-yl, 1,2-dihydropyridin-5-yl, 1,2-dihydropyridin-6-yl, 1,2,5,6-tetrahydropyridin-5-yl, 1,2,3,6-tetrahydropyridin-4-yl, hexahydrocyclopentapyrrol-2(1H)-yl, hexahydropyrrolo[3,2-b]pyrrol-1(2H)-yl, hexahydropyrrolo[3,4-b]pyrrol-1(2H)-yl, (3aS,6aS)-hexahydropyrrolo[3,4-b]pyrrol-1(2H)-yl, hexahydropyrrolo[3,4-b]pyrrol-5(1H)-yl, (3aS,6aS)-hexahydropyrrolo[3,4-b]pyrrol-5(1H)-yl, (3aR,6aR)-hexahydropyrrolo[3,4-b]pyrrol-5(1H)-yl, hexahydropyrrolo[3,4-c]pyrrol-1(1H)-yl, hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl, hexahydropyrrolo[3,4-c]pyrrol-5(1H)-yl, (3aR,6aS)-hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl, octahydro-2H-pyrrolo[3,4-c]pyridin-2-yl, octahydro-5H-pyrrolo[3,2-c]pyridin-5-yl, octahydro-6H-pyrrolo[3,4-b]pyridin-6-yl, (4aR,7aR)-octahydro-6H-pyrrolo[3,4-b]pyridin-6-yl, (4aS,7aS)-octahydro-6H-pyrrolo[3,4-b]pyridin-6-yl, hexahydropyrrolo[1,2-a]pyrazin-6(2H)-one, hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl, (7R,8aS)-hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl, (8aS)-hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl, (8aR)-hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl, hexahydro-1H-cyclobuta[1.2-c:1,4-c′]dipyrrol-2(3H)-yl, (8aS)-octahydropyrrolo[1,2-a]pyrazin-2(1H)-yl, (8aR)-octahydropyrrolo[1,2-a]pyrazin-2(1H)-yl, octahydro-2H-pyrido[1,2-a]pyrazin-2-yl, hexahydropyrrolo[3,4-b][1,4]oxazin-6(2H)-yl, 5-azaspiro[2.4]heptan-5-yl, 2-oxa-6-azaspiro[3.4]octan-6-yl, 3-azabicyclo[3.1.0]hexan-3-yl, 8-azabicyclo[3.2.1]octan-3-yl, (1R,5S)-8-azabicyclo[3.2.1]octan-3-yl, 8-azabicyclo[3.2.1]oct-2-en-3-yl, (1R,5S)-8-azabicyclo[3.2.1]oct-2-en-3-yl, 9-azabicyclo[3.3.1]nonan-3-yl, (1R,5S)-9-azabicyclo[3.3.1]nonan-3-yl, 2,5-diazabicyclo[2.2.1]heptan-2-yl, (1S,4S)-2,5-diazabicyclo[2.2.1]heptan-2-yl, 1,4-diazabicyclo[3.1.1]heptan-4-yl, 3,6-diazabicyclo[3.2.0]heptan-3-yl, 3,6-diazabicyclo[3.2.0]heptan-6-yl, 2,5-diazabicyclo[2.2.2]octan-2-yl, 1,4-diazabicyclo[3.2.1]octan-4-yl, 3,8-diazabicyclo[3.2.1]octan-3-yl, (1R,5S)-3,8-diazabicyclo[3.2.1]octan-3-yl, 1,4-diazabicyclo[3.2.2]nonan-4-yl, azaspiro[3.3]heptan-2-yl, 4,7-diazaspiro[2.5]octan-4-yl, 4,7-diazaspiro[2.5]octan-7-yl, 2,6-diazaspiro[3.3]heptan-2-yl, 2,6-diazaspiro[3.4]octan-2-yl, 2,6-diazaspiro[3.4]octan-6-yl, 1,7,-diazaspiro[4.4]nonan-1-yl, 1,7-diazaspiro[4.4]nonan-7-yl, 1,7-diazaspiro[3.5]nonan-7-yl, 2,6-diazaspiro[3.5]nonan-2-yl, 2,6-diazaspiro[3.5]nonan-6-yl, 2,7-diazaspiro[3.5]nonan-2-yl, 2,7-diazaspiro[3.5]nonan-7-yl, 5,8-diazaspiro[3.5]nonan-8-yl, 2,7-diazaspiro[4.4]nonan-2-yl, 2,7-diazaspiro[4.5]decan-2-yl, 2,7-diazaspiro[4.5]decan-7-yl, and 2,8-diazaspiro[4.5]decan-8-yl. 6,9-diazaspiro[4.5]dec-9-yl, and 7-azadispiro[5.1.5⁸.3⁶]hexadecan-15-yl, optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂.

Another aspect includes a compound of Formula (I), wherein B is heterocyclyl selected from pyrrolidin-1-yl, piperidin-4-yl, hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl, 8-azabicyclo[3.2.1]octan-3-yl, 2,6-diazaspiro[3.4]octan-2-yl, and 7-azadispiro[5.1.5⁸.3⁶]hexadecan-15-yl, optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂.

Another aspect includes a compound of Formula (I), wherein B is heterocyclyl selected from pyrrolidin-1-yl and piperidin-4-yl, optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂.

One aspect includes a compound of Formula (I), wherein R₂ is selected from halogen, C₁₋₄alkyl, deutero-C₁₋₄alkyl, amino, C₁₋₄alkyl-amino, and (C₁₋₄alkyl)₂-amino.

Another aspect includes a compound of Formula (I), wherein R₂ is selected from C₁₋₄alkyl and C₁₋₄alkyl-amino.

Another aspect includes a compound of Formula (I), wherein R₂ is C₁₋₄alkyl selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl.

Another aspect includes a compound of Formula (I), wherein R₂ is methyl.

Another aspect includes a compound of Formula (I), wherein R₂ is C₁₋₄alkyl-amino, wherein C₁₋₄alkyl is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl.

Another aspect includes a compound of Formula (I), wherein R₂ is C₁₋₄alkyl-amino, wherein C₁₋₄alkyl is tert-butyl.

Another aspect includes a compound of Formula (I), wherein R₂ is C₁₋₄alkyl-amino, wherein C₁₋₄alkyl is tert-butylamino.

One aspect includes a compound of Formula (I), wherein R₃ is selected from halogen, hydroxyl, cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, C₁₋₄alkyl-amino, (C₁₋₄alkyl)₂-amino, C₁₋₄alkoxy, halo-C₁₋₄alkoxy, heteroaryl, heterocyclyl, and phenyl,

wherein heteroaryl is a 3-7 membered monocyclic or 6-10 membered bicyclic ring system having 1, 2, 3, or 4 heteroatom ring members independently selected from N, O, or S,

wherein heterocyclyl is a saturated or partially unsaturated 3-7 membered monocyclic, 6-10 membered bicyclic or 13-16 membered polycyclic ring system having 1, 2, or 3 heteroatom ring members independently selected from N, O, or S, and

wherein each instance of phenyl, heteroaryl or heterocyclyl is optionally substituted with 1 or 2 substituents each selected from R₄.

Another aspect includes a compound of Formula (I), wherein R₃ is selected from halogen, hydroxyl, cyano, C₁₋₄alkyl, and heteroaryl,

wherein heteroaryl is a 3-7 membered monocyclic or 6-10 membered bicyclic ring system having 1, 2, 3, or 4 heteroatom ring members independently selected from N, O, or S,

wherein each instance of heteroaryl is optionally substituted with 1 or 2 substituents each selected from R₄.

Another aspect includes a compound of Formula (I), wherein R₃ is halogen selected from bromo, chloro, fluoro, and iodo.

Another aspect includes a compound of Formula (I), wherein R₃ is halogen selected from chloro and fluoro.

Another aspect includes a compound of Formula (I), wherein R₃ is chloro.

Another aspect includes a compound of Formula (I), wherein R₃ is fluoro.

Another aspect includes a compound of Formula (I), wherein R₃ is hydroxyl.

Another aspect includes a compound of Formula (I), wherein R₃ is cyano.

Another aspect includes a compound of Formula (I), wherein R₃ is C₁₋₄alkyl selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl.

Another aspect includes a compound of Formula (I), wherein R₃ is methyl.

Another aspect includes a compound of Formula (I), wherein R₃ is heteroaryl selected from thienyl, 1H-pyrazolyl, 1H-imidazolyl, 1,3-thiazolyl, oxazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,4-thiadiazolyl, 1H-1,2,3-triazolyl, 2H-1,2,3-triazolyl, 1H-1,2,4-triazolyl, 1H-tetrazolyl, 2H-tetrazolyl, pyridinyl, pyridin-2(1H)-on-yl, pyrimidinyl, pyrimidin-4(3H)-on-yl, pyridazinyl, pyridazin-3(2H)-on-yl, 1,2,4-triazinyl, 1,3,5-triazinyl, 1H-indolyl, 1H-indazolyl, 2H-indazolyl, indolizinyl, benzofuranyl, benzothienyl, 1H-benzimidazolyl, 1,3-benzoxazolyl, 1,3-benzothiazolyl, 1,3-benzodioxolyl, 1,2,3-benzotriazolyl, 9H-purinyl, furo[3,2-b]pyridinyl, furo[3,2-c]pyridinyl, furo[2,3-c]pyridinyl, 1,3-oxazolo[5,4-b]pyridinyl, thieno[3,2-c]pyridinyl, thieno[2,3-d]pyrimidinyl, 1H-pyrrolo[2,3-b]pyridinyl, 1H-pyrrolo[2,3-c]pyridinyl, pyrrolo[1,2-a]pyrimidinyl, pyrrolo[1,2-a]pyrazinyl, pyrrolo[1,2-b]pyridazinyl, pyrazolo[1,5-a]pyridin-yl, pyrazolo[1,5-a]pyridinyl, 1H-pyrazolo[3,4-b]pyrazinyl, 1H-pyrazolo[3,4-b]pyridinyl, 1H-pyrazolo[3,4-b]pyridinyl, 1H-pyrazolo[3,4-c]pyridinyl, 1H-pyrazolo[3,4-c]pyridinyl, 1H-pyrazolo[4,3-b]pyridinyl, 1H-pyrazolo[4,3-b]pyridinyl, 1H-pyrazolo[4,3-d]pyrimidinyl, 2H-pyrazolo[4,3-b]pyridinyl, 2H-pyrazolo[4,3-c]pyridin-yl, 5H-pyrrolo[2,3-b]pyrazinyl, pyrazolo[1,5-a]pyrazinyl, imidazo[1,2-a]pyridinyl, imidazo[1,2-a]pyridinyl, imidazo[1,2-a]pyrimidinyl, imidazo[1,2-a]pyrimidinyl, imidazo[1,2-c]pyrimidinyl, imidazo[1,2-b]pyridazinyl, imidazo[1,2-b]pyridazinyl, imidazo[1,2-a]pyrazinyl, imidazo[1,2-a]pyrazinyl, 1H-imidazo[4,5-b]pyridinyl, 3H-imidazo[4,5-b]pyridinyl, imidazo[2,1-b][1,3]thiazolyl, imidazo[2,1-b][1,3,4]thiadiazolyl, [1,3]oxazolo[4,5-b]pyridinyl, [1,2,3]triazolo[1,5-a]pyridinyl, [1,2,3]triazolo[1,5-a]pyridinyl, 1H-[1,2,3]triazolo[4,5-b]pyridinyl, 3H-[1,2,3]triazolo[4,5-b]pyridinyl, tetrazolo[1,5-a]pyridinyl, tetrazolo[1,5-b]pyridazinyl, quinolinyl, isoquinolinyl, and quinoxalinyl, optionally substituted with 1 or 2 substituents each selected from R₄.

Another aspect includes a compound of Formula (I), wherein R₃ is heteroaryl selected from 1H-pyrazolyl, 1H-imidazolyl, 2H-1,2,3-triazolyl, 1H-1,2,4-triazolyl, pyridinyl, pyridin-2(1H)-on-yl, pyrimidinyl, 1,3,5-triazinyl, imidazo[1,2-b]pyridazinyl, and imidazo[1,2-a]pyrazinyl, optionally substituted with 1 or 2 substituents each selected from R₄.

Another aspect includes a compound of Formula (I), wherein R₃ is heteroaryl selected from thien-2-yl, thien-3-yl, 1H-pyrazol-1-yl, 1H-pyrazol-3-yl, 1H-pyrazol-4-yl, 1H-pyrazol-5-yl, 1H-imidazol-1-yl, 1H-imidazol-4-yl, 1,3-thiazol-2-yl, 1,3-thiazol-5-yl, oxazol-2-yl, oxazol-4-yl, oxazol-5-yl, 1,2,4-oxadiazol-3-yl, 1,3,4-oxadiazol-2-yl, 1,2,4-thiadiazol-5-yl, 1H-1,2,3-triazol-1-yl, 1H-1,2,3-triazol-4-yl, 1H-1,2,3-triazol-5-yl, 2H-1,2,3-triazol-2-yl, 2H-1,2,3-triazol-4-yl, 1H-1,2,4-triazol-1-yl, 1H-1,2,4-triazol-3-yl, 1H-1,2,4-triazol-5-yl, 1H-tetrazol-1-yl, 1H-tetrazol-5-yl, 2H-tetrazol-2-yl, 2H-tetrazol-5-yl, pyridin-2-yl, pyridin-3-yl, pyridin-4-yl, pyridin-2(1H)-on-4-yl, pyridin-2(1H)-on-5-yl, pyridin-2(1H)-on-6-yl, pyrimidin-2-yl, pyrimidin-4-yl, pyrimidin-5-yl, pyrimidin-4(3H)-on-6-yl, pyridazin-3-yl, pyridazin-4-yl, pyridazin-3(2H)-on-5-yl, 1,2,4-triazin-3-yl, 1,3,5-triazin-2-yl, 1H-indol-3-yl, 1H-indol-4-yl, 1H-indol-5-yl, 1H-indol-6-yl, 1H-indazol-5-yl, 2H-indazol-5-yl, indolizin-2-yl, benzofuran-2-yl, benzofuran-5-yl, benzothien-2-yl, benzothien-3-yl, 1H-benzimidazol-2-yl, 1H-benzimidazol-5-yl, 1H-benzimidazol-6-yl, 1,3-benzoxazol-2-yl, 1,3-benzoxazol-5-yl, 1,3-benzoxazol-6-yl, 1,3-benzothiazol-2-yl, 1,3-benzothiazol-5-yl, 1,3-benzothiazol-6-yl, 1,3-benzodioxol-5-yl, 1,2,3-benzotriazol-5-yl, 9H-purin-8-yl, furo[3,2-b]pyridin-2-yl, furo[3,2-c]pyridin-2-yl, furo[2,3-c]pyridin-2-yl, 1,3-oxazolo[5,4-b]pyridin-5-yl, thieno[3,2-c]pyridin-2-yl, thieno[2,3-d]pyrimidin-6-yl, 1H-pyrrolo[2,3-b]pyridin-5-yl, 1H-pyrrolo[2,3-c]pyridin-4-yl, pyrrolo[1,2-a]pyrimidin-7-yl, pyrrolo[1,2-a]pyrazin-7-yl, pyrrolo[1,2-b]pyridazin-2-yl, pyrazolo[1,5-a]pyridin-2-yl, pyrazolo[1,5-a]pyridin-5-yl, 1H-pyrazolo[3,4-b]pyrazin-5-yl, 1H-pyrazolo[3,4-b]pyridin-5-yl, 1H-pyrazolo[3,4-b]pyridin-6-yl, 1H-pyrazolo[3,4-c]pyridin-1-yl, 1H-pyrazolo[3,4-c]pyridin-5-yl, 1H-pyrazolo[4,3-b]pyridin-5-yl, 1H-pyrazolo[4,3-b]pyridin-6-yl, 1H-pyrazolo[4,3-d]pyrimidin-5-yl, 2H-pyrazolo[4,3-b]pyridin-5-yl, 2H-pyrazolo[4,3-c]pyridin-5-yl, 5H-pyrrolo[2,3-b]pyrazin-2-yl, pyrazolo[1,5-a]pyrazin-2-yl, imidazo[1,2-a]pyridin-2-yl, imidazo[1,2-a]pyridin-6-yl, imidazo[1,2-a]pyrimidin-2-yl, imidazo[1,2-a]pyrimidin-6-yl, imidazo[1,2-c]pyrimidin-2-yl, imidazo[1,2-b]pyridazin-2-yl, imidazo[1,2-b]pyridazin-6-yl, imidazo[1,2-a]pyrazin-2-yl, imidazo[1,2-a]pyrazin-6-yl, 1H-imidazo[4,5-b]pyridin-5-yl, 3H-imidazo[4,5-b]pyridin-5-yl, imidazo[2,1-b][1,3]thiazol-6-yl, imidazo[2,1-b][1,3,4]thiadiazol-6-yl, [1,3]oxazolo[4,5-b]pyridin-2-yl, [1,2,3]triazolo[1,5-a]pyridin-5-yl, [1,2,3]triazolo[1,5-a]pyridin-6-yl, 1H-[1,2,3]triazolo[4,5-b]pyridin-5-yl, 3H-[1,2,3]triazolo[4,5-b]pyridin-5-yl, tetrazolo[1,5-a]pyridin-7-yl, tetrazolo[1,5-b]pyridazin-7-yl, quinolin-6-yl, isoquinolin-6-yl, and quinoxalin-2-yl, optionally substituted with 1 or 2 substituents each selected from R₄.

Another aspect includes a compound of Formula (I), wherein R₃ is heteroaryl selected from 1H-pyrazol-1-yl, 1H-pyrazol-3-yl, 1H-pyrazol-4-yl, 1H-imidazol-1-yl, 2H-1,2,3-triazol-2-yl, 1H-1,2,4-triazol-1-yl, pyridin-2-yl, pyridin-3-yl, pyridin-4-yl, pyridin-2(H)-on-4-yl, pyrimidin-2-yl, pyrimidin-4-yl, 1,3,5-triazin-2-yl, imidazo[1,2-b]pyridazin-6-yl, and imidazo[1,2-a]pyrazin-6-yl, optionally substituted with 1 or 2 substituents each selected from R₄.

One aspect includes a compound of Formula (I), wherein R₄ is selected from halogen, hydroxyl, cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, C₁₋₄alkyl-amino, (C₁₋₄alkyl)₂-amino, C₁₋₄alkoxy, and halo-C₁₋₄alkoxy.

Another aspect includes a compound of Formula (I), wherein R₄ is selected from halogen, hydroxyl, cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, and C₁₋₄alkoxy.

Another aspect includes a compound of Formula (I), wherein R₄ is halogen selected from bromo, chloro, fluoro, and iodo.

Another aspect includes a compound of Formula (I), wherein R₄ is halogen selected from chloro and fluoro.

Another aspect includes a compound of Formula (I), wherein R₄ is chloro.

Another aspect includes a compound of Formula (I), wherein R₄ is fluoro.

Another aspect includes a compound of Formula (I), wherein R₄ is hydroxyl.

Another aspect includes a compound of Formula (I), wherein R₄ is cyano.

Another aspect includes a compound of Formula (I), wherein R₄ is C₁₋₄alkyl selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl.

Another aspect includes a compound of Formula (I), wherein R₄ is methyl.

Another aspect includes a compound of Formula (I), wherein R₄ is deutero-C₁₋₄alkyl wherein C₁₋₄alkyl is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl partially or completely substituted with one or more deuterium atoms where allowed by available valences.

Another aspect includes a compound of Formula (I), wherein R₄ is (²H₃)methyl.

Another aspect includes a compound of Formula (I), wherein R₄ is halo-C₁₋₄alkyl wherein C₁₋₄alkyl is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl partially or completely substituted with one or more halogen atoms where allowed by available valences.

Another aspect includes a compound of Formula (I), wherein R₄ is trifluoromethyl.

Another aspect includes a compound of Formula (I), wherein R₄ is amino.

Another aspect includes a compound of Formula (I), wherein R₄ is C₁₋₄alkoxy selected from methoxy, ethoxy, propoxy, isopropoxy, butoxy, and tert-butoxy.

Another aspect includes a compound of Formula (I), wherein R₄ methoxy.

One aspect includes a compound of Formula (I), wherein n is 1, 2 or 3.

Another aspect includes a compound of Formula (I), wherein n is 2.

Another aspect includes a compound of Formula (I), wherein n is 3.

An aspect of the compound of Formula (I) or a form thereof includes a compound selected from the group consisting of:

wherein a form of the compound is selected from the group consisting of a salt, hydrate, solvate, racemate, enantiomer, diastereomer, stereoisomer, and tautomer form thereof.

An aspect the compound of Formula (I) or a form thereof (wherein compound number (#¹) indicates that the salt form was isolated) includes a compound selected from the group consisting of:

Cpd Name  1 4-(3-hydroxy-4-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-   yl}phenyl)pyridin-2-ol  2¹ 5-(1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)oxy]pyrazin-2-yl}phenol  3 2-{5-[(7-azadispiro[5.1.5⁸.3⁶]hexadecan-15-yl)(methyl)amino]pyrazin-2-yl}-5-(1H- pyrazol-4-yl)phenol  4 5-[2,5-dichloro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin- 4-yl)pyrazin-2-amine  5 5-(1H-imidazol-1-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2- yl}phenol  6¹ 2-[5-(hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl)pyrazin-2-yl]-5-(1H-pyrazol-4- yl)phenol  7¹ 2-{5-[(piperidin-4-yl)oxy]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol  8¹ 2-{5-[(piperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol   2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-[5-  9 (trifluoromethyl)-1H-pyrazol-4-yl]phenol 10¹ 2-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]-5-[(2,2,6,6-tetramethylpiperidin-4- yl)oxy]pyrazine 11 5-[2-fluoro-5-methyl-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6- tetramethylpiperidin-4-yl)pyrazin-2-amine 12 5-(5-methyl-1H-pyrazol-4-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol 13¹ 5-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin- 4-yl)pyrazin-2-amine 14 5-(3-amino-1H-pyrazol-1-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol 15 5-[2,5-difluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin- 4-yl)pyrazin-2-amine 16 5-[3-fluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4- yl)pyrazin-2-amine 17 5-[3,5-difluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin- 4-yl)pyrazin-2-amine 18 4-(3-hydroxy-4-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2- yl}phenyl)-1-methylpyridin-2(1H)-one 19 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-1- yl)phenol 20 2-{5-[methyl(piperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol 21 2-[5-(2,6-diazaspiro[3.4]octan-2-yl)pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol 22 4-fluoro-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(1H- pyrazol-4-yl)phenol 23 5-[5-chloro-2-fluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6- tetramethylpiperidin-4-yl)pyrazin-2-amine 24 4-fluoro-5-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-2-(1H- pyrazol-4-yl)benzonitrile 25¹ 2-[5-(8-azabicyclo[3.2.1]oct-3-yloxy)pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol 26¹ 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4- yl)phenol 27 5-(1-methyl-1H-pyrazol-4-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl} phenol 28¹ 5-[1-(²H₃)methyl-1H-pyrazo1-4-yl]-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol 29 (5-(2-hydroxy-4-(1H-pyrazol-4-yl)phenyl)pyrazin-2-yl)(2,2,6,6-tetramethylpiperidin-4- yl)methanone 30 2-(5-(2-hydroxy-4-(1H-pyrazol-4-yl)phenyl)pyrazin-2-yl)-2-(2,2,6,6- tetramethylpiperidin-4-yl)acetonitrile 31 2-(5-(amino(2,2,6,6-tetramethylpiperidin-4-yl)methyl)pyrazin-2-yl)-5-(1H-pyrazol-4- yl)phenol 32 2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)-5-(1,3,5-triazin-2- yl)phenol 33 4-(3-hydroxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2- yl)phenyl)-1,3,5-triazin-2-ol 34 5-(4-amino-1,3,5-triazin-2-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino)pyrazin-2-yl)phenol 35 5-(4-chloro-1,3,5-triazin-2-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino)pyrazin-2-yl)phenol 36 5-(5-chloro-1H-pyrazol-4-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino)pyrazin-2-yl)phenol 37 4-(3-hydroxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2- yl)phenyl)-1H-pyrazole-5-carbonitrile 38 5-(1,5-dimethyl-1H-pyrazol-4-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino)pyrazin-2-yl)phenol 39 5-(5-chloro-l-methyl-1H-pyrazol-4-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino)pyrazin-2-yl)phenol 40 4-(3-hydroxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2- yl)phenyl)-1-methyl-1H-pyrazole-5-carbonitrile 41 5-[2,3-difluoro-4-(4-methyl-1H-imidazol-1-yl)phenyl]-N-methyl-N-(2,2,6,6- tetramethylpiperidin-4-yl)pyrazin-2-amine 42 5-[2,5-difluoro-4-(3-methyl-1H-1,2,4-triazol-1-yl)phenyl]-N-methyl-N-(2,2,6,6- tetramethylpiperidin-4-yl)pyrazin-2-amine 43¹ 5-(3-fluoro-1H-pyrazol-4-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol 44¹ 5-(pyridin-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl} phenol 45¹ 5-(pyridin-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol 46¹ 5-(1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2- yl}phenol 47¹ 5-(pyrimidin-2-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl} phenol 48¹ 5-(pyridin-2-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol 49¹ 5-(6-methoxypyrimidin-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol 50¹ 5-(1H-imidazol-1-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2- yl}phenol 51¹ 2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(2H-1,2,3-triazol-2- yl)phenol 52¹ 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol 53¹ 5-(imidazo[1,2-a]pyrazin-6-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol 54¹ 5-(1-methyl-1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol 55 5-(1-methyl-1H-pyrazol-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol 56¹ 5-(imidazo[1,2-b]pyridazin-6-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol 57¹ 5-(5-fluoro-1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol 58¹ 5-(1H-pyrazol-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2- yl}phenol 59¹ 5-(4-fluoro-1H-pyrazol-1-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol 60¹ 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-[1-(²H₃)methyl-1H-pyrazol- 4-yl]phenol 61¹ 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(2H-1,2,3- triazol-2-yl)phenol 62¹ 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(1-methyl-1H-pyrazol-4- yl)phenol 63¹ N-tert-butyl-1-{5-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]pyrazin-2-yl}pyrrolidin-3- amine 64¹ N-tert-butyl-1-{5-[2,5-difluoro-4-(1H-pyrazol-4-yl)phenyl]pyrazin-2-yl}pyrrolidin-3- amine, and 65¹ 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(3-fluoro-1H-pyrazol-4- yl)phenol; wherein a form of the compound is selected from the group consisting of a salt, hydrate, solvate, racemate, enantiomer, diastereomer, stereoisomer, and tautomer form thereof.

Another aspect of the compound of Formula (I) or a form thereof is a compound salt selected from the group consisting of:

Cpd Name 2 5-(1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)oxy]pyrazin-2-yl}phenol hydrochloride 6 2-[5-(hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl)pyrazin-2-yl]-5-(1H-pyrazol-4- yl)phenol tetrahydrochloride 7 2-{5-[(piperidin-4-yl)oxy]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol trihydrochloride 8 2-{5-[(piperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol tetrahydrochloride 10 2-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]-5-[(2,2,6,6-tetramethylpiperidin-4- yl)oxy]pyrazine trihydrochloride 13 5-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-[(2,2,6,6-tetramethylpiperidin- 4-yl)pyrazin-2-amine hydrochloride 25 2-[5-(8-azabicyclo[3.2.1]oct-3-yloxy)pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol hydrochloride 26 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4- yl)phenol hydrobromide 28 5-[1-(²H₃)methyl-1H-pyrazol-4-yl]-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol dihydrochloride 43 5-(3-fluoro-1H-pyrazol-4-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol dihydrochloride 44 5-(pyridin-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate 45 5-(pyridin-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate 46 5-(1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2- yl}phenol formate 47 5-(pyrimidin-2-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate 48 5-(pyridin-2-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate 49 5-(6-methoxypyrimidin-4-yl)-2-{5-](2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol formate 50 5-(1H-imidazol- 1-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2- yl}phenol formate 51 2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(2H-1,2,3-triazol-2- yl)phenol formate 52 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol dihydrochloride 53 5-(imidazo[1,2-a]pyrazin-6-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol formate 54 5-(1-methyl-1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol formate 56 5-(imidazo[1,2-b]pyridazin-6-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4- yl)amino]pyrazin-2-yl}phenol formate 57 5-(5-fluoro-1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol formate 58 5-(1H-pyrazol-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2- yl}phenol formate 59 5-(4-fluoro-1H-pyrazol-1-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin- 2-yl}phenol formate 60 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl] pyrazin-2-yl}-5-[1-(²H₃)methyl-1H-pyrazol- 4-yl]phenol dihydrochloride 61 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(2H-1,2,3- triazol-2-yl)phenol dihydrochloride 62 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(1-methyl-1H-pyrazol-4- yl)phenol dihydrochloride 63 N-tert-butyl-1-{5-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]pyrazin-2-yl}pyrrolidin-3- amine dihydrochloride 64 N-tert-butyl-1-{5-[2,5-difluoro-4-(1H-pyrazol-4-yl)phenyl]pyrazin-2-yl}pyrrolidin-3- amine dihydrochloride, and 65 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl] pyrazin-2-yl}-5-(3-fluoro-1H-pyrazol-4- yl)phenol dihydrochloride; wherein a form of the compound is selected from the group consisting of a salt, hydrate, solvate, racemate, enantiomer, diastereomer, stereoisomer, and tautomer form thereof.

An aspect of the present description includes a method for preventing, treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound of Formula (I) or a form thereof.

An aspect of the present description includes a method for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound of Formula (I) or a form thereof.

Another aspect of the present description includes a method for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound salt of Formula (I) or a form thereof.

An aspect of the present description includes a method for use of a compound of Formula (I) or a form or composition thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form or composition thereof.

Another aspect of the present description includes a method for use of a compound salt of Formula (I) or a form or composition thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound salt of Formula (I) or a form thereof.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form thereof.

Another aspect of the present description includes a use for a compound salt of Formula (I) or a form thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound salt of Formula (I) or a form thereof.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in the manufacture of a medicament for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the medicament.

Another aspect of the present description includes a use for a compound salt of Formula (I) or a form thereof in the manufacture of a medicament for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the medicament.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in a combination product with one or more therapeutic agents for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form thereof in combination with an effective amount of the one or more agents.

Another aspect of the present description includes a use for a compound salt of Formula (I) or a form thereof in a combination product with one or more therapeutic agents for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound salt of Formula (I) or a form thereof in combination with an effective amount of the one or more agents.

Chemical Definitions

The chemical terms used above and throughout the description herein, unless specifically defined otherwise, shall be understood by one of ordinary skill in the art to have the following indicated meanings.

As used herein, the term “C₁₋₄alkyl” generally refers to saturated hydrocarbon radicals having from one to four carbon atoms in a straight or branched chain configuration, including, but not limited to, methyl, ethyl, n-propyl (also referred to as propyl or propanyl), isopropyl, n-butyl (also referred to as butyl or butanyl), isobutyl, sec-butyl, tert-butyl and the like. A C₁₋₄alkyl radical is optionally substituted with substituent species as described herein where allowed by available valences.

As used herein, the term “C₂₋₄alkenyl” generally refers to partially unsaturated hydrocarbon radicals having from two to four carbon atoms in a straight or branched chain configuration and one or more carbon-carbon double bonds therein, including, but not limited to, ethenyl (also referred to as vinyl), allyl, propenyl and the like. A C₂₋₄alkenyl radical is optionally substituted with substituent species as described herein where allowed by available valences.

As used herein, the term “C₂₋₈alkynyl” generally refers to partially unsaturated hydrocarbon radicals having from two to eight carbon atoms in a straight or branched chain configuration and one or more carbon-carbon triple bonds therein, including, but not limited to, ethynyl, propynyl, butynyl and the like. In certain aspects, C₂₋₈alkynyl includes, but is not limited to, C₂₋₆alkynyl, C₂₋₄alkynyl and the like. A C₂₋₈alkynyl radical is optionally substituted with substituent species as described herein where allowed by available valences.

As used herein, the term “C₁₋₄alkoxy” generally refers to saturated hydrocarbon radicals having from one to four carbon atoms in a straight or branched chain configuration of the formula: —O—C₁₋₄alkyl, including, but not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy and the like. A C₁₋₄₄alkoxy radical is optionally substituted with substituent species as described herein where allowed by available valences.

As used herein, the term “C₃₋₇cycloalkyl” generally refers to a saturated or partially unsaturated monocyclic, bicyclic or polycyclic hydrocarbon radical, including, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexenyl, cycloheptyl, and the like. A C₃₋₇cycloalkyl radical is optionally substituted with substituent species as described herein where allowed by available valences.

As used herein, the term “aryl” generally refers to a monocyclic, bicyclic or polycyclic aromatic carbon atom ring structure radical, including, but not limited to, phenyl, naphthyl, anthracenyl, fluorenyl, azulenyl, phenanthrenyl and the like. An aryl radical is optionally substituted with substituent species as described herein where allowed by available valences.

As used herein, the term “heteroaryl” generally refers to a monocyclic, bicyclic or polycyclic aromatic carbon atom ring structure radical in which one or more carbon atom ring members have been replaced, where allowed by structural stability, with one or more heteroatoms, such as an O, S or N atom, including, but not limited to, furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxazolyl, 1,3-thiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, indolyl, indazolyl, indolizinyl, isoindolyl, benzofuranyl, benzothienyl, benzoimidazolyl, 1,3-benzothiazolyl, 1,3-benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, 1,3-diazinyl, 1,2-diazinyl, 1,2-diazolyl, 1,4-diazanaphthalenyl, acridinyl, furo[3,2-b]pyridinyl, furo[3,2-c]pyridinyl, furo[2,3-c]pyridinyl, 6H-thieno[2,3-b]pyrrolyl, thieno[3,2-c]pyridinyl, thieno[2,3-d]pyrimidinyl, 1H-pyrrolo[2,3-b]pyridinyl, 1H-pyrrolo[2,3-c]pyridinyl, 1H-pyrrolo[3,2-b]pyridinyl, pyrrolo[1,2-a]pyrazinyl, pyrrolo[1,2-b]pyridazinyl, pyrazolo[1,5-a]pyridinyl, pyrazolo[1,5-a]pyrazinyl, imidazo[1,2-a]pyridinyl, 3H-imidazo[4,5-b]pyridinyl, imidazo[1,2-a]pyrimidinyl, imidazo[1,2-c]pyrimidinyl, imidazo[1,2-b]pyridazinyl, imidazo[1,2-a]pyrazinyl, imidazo[2,1-b][1,3]thiazolyl, imidazo[2,1-b][1,3,4]thiadiazolyl, [1,2,4]triazolo[1,5-a]pyridinyl, [1,2,4]triazolo[4,3-a]pyridinyl and the like. A heteroaryl radical is optionally substituted on a carbon or nitrogen atom ring member with substituent species as described herein where allowed by available valences.

In certain aspects, the nomenclature for a heteroaryl radical may differ, such as in non-limiting examples where furanyl may also be referred to as furyl, thienyl may also be referred to as thiophenyl, pyridinyl may also be referred to as pyridyl, benzothienyl may also be referred to as benzothiophenyl and 1,3-benzoxazolyl may also be referred to as 1,3-benzooxazolyl.

In certain other aspects, the term for a heteroaryl radical may also include other regioisomers, such as in non-limiting examples where the term pyrrolyl may also include 2H-pyrrolyl, 3H-pyrrolyl and the like, the term pyrazolyl may also include 1H-pyrazolyl and the like, the term imidazolyl may also include 1H-imidazolyl and the like, the term triazolyl may also include 1H-1,2,3-triazolyl and the like, the term oxadiazolyl may also include 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl and the like, the term tetrazolyl may also include 1H-tetrazolyl, 2H-tetrazolyl and the like, the term indolyl may also include 1H-indolyl and the like, the term indazolyl may also include 1H-indazolyl, 2H-indazolyl and the like, the term benzoimidazolyl may also include 1H-benzoimidazolyl and the term purinyl may also include 9H-purinyl and the like.

As used herein, the term “heterocyclyl” generally refers to a saturated or partially unsaturated monocyclic, bicyclic or polycyclic carbon atom ring structure radical in which one or more carbon atom ring members have been replaced, where allowed by structural stability, with a heteroatom, such as an O, S or N atom, including, but not limited to, oxiranyl, oxetanyl, azetidinyl, tetrahydrofuranyl, pyrrolinyl, pyrrolidinyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, isoxazolinyl, isoxazolidinyl, isothiazolinyl, isothiazolidinyl, oxazolinyl, oxazolidinyl, thiazolinyl, thiazolidinyl, triazolinyl, triazolidinyl, oxadiazolinyl, oxadiazolidinyl, thiadiazolinyl, thiadiazolidinyl, tetrazolinyl, tetrazolidinyl, pyranyl, dihydro-2H-pyranyl, thiopyranyl, 1,3-dioxanyl, 1,2,5,6-tetrahydropyridinyl, 1,2,3,6-tetrahydropyridinyl, piperidinyl, piperazinyl, morpholinyl, thiomorpholinyl, 1,4-diazepanyl, 1,3-benzodioxolyl, 1,4-benzodioxanyl, 2,3-dihydro-1,4-benzodioxinyl, hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, (3aS,6aS)-hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, (3aR,6aR)-hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, hexahydropyrrolo[3,4-b]pyrrol-(2H)-yl, (3aS,6aS)-hexahydropyrrolo[3,4-b]pyrrol-(2H)-yl, (3aR,6aR)-hexahydropyrrolo[3,4-b]pyrrol-(2H)-yl, hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, (3aR,6aS)-hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, (3aR,6aR)-hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, octahydro-5H-pyrrolo[3,2-c]pyridinyl, octahydro-6H-pyrrolo[3,4-b]pyridinyl, (4aR,7aR)-octahydro-6H-pyrrolo[3,4-b]pyridinyl, (4aS,7aS)-octahydro-6H-pyrrolo[3,4-b]pyridinyl, hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (7R,8aS)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aS)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aR)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aS)-octahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aR)-octahydropyrrolo[1,2-a]pyrazin-(1H)-yl, hexahydropyrrolo[1,2-a]pyrazin-(2H)-one, octahydro-2H-pyrido[1,2-a]pyrazinyl, 3-azabicyclo[3.1.0]hexyl, (1R,5S)-3-azabicyclo[3.1.0]hexyl, 8-azabicyclo[3.2.1]octyl, (1R,5S)-8-azabicyclo[3.2.1]octyl, 8-azabicyclo[3.2.1]oct-2-enyl, (1R,5S)-8-azabicyclo[3.2.1]oct-2-enyl, 9-azabicyclo[3.3.1]nonyl, (1R,5S)-9-azabicyclo[3.3.1]nonyl, 2,5-diazabicyclo[2.2.1]heptyl, (1S,4S)-2,5-diazabicyclo[2.2.1]heptyl, 2,5-diazabicyclo[2.2.2]octyl, 3,8-diazabicyclo[3.2.1]octyl, (1R,5S)-3,8-diazabicyclo[3.2.1]octyl, 1,4-diazabicyclo[3.2.2]nonyl, azaspiro[3.3]heptyl, 2,6-diazaspiro[3.3]heptyl, 2,6-diazaspiro[3.4]octyl, 2,7-diazaspiro[3.5]nonyl, 5,8-diazaspiro[3.5]nonyl, 2,7-diazaspiro[4.4]nonyl, 6,9-diazaspiro[4.5]decyl, 7-azadispiro[5.1.5⁸.3⁶]hexadecanyl and the like. A heterocyclyl radical is optionally substituted on a carbon or nitrogen atom ring member with substituent species as described herein where allowed by available valences.

In certain aspects, the nomenclature for a heterocyclyl radical may differ, such as in non-limiting examples where 1,3-benzodioxolyl may also be referred to as benzo[d][1,3]dioxolyl and 2,3-dihydro-1,4-benzodioxinyl may also be referred to as 2,3-dihydrobenzo[b][1,4]dioxinyl.

As used herein, the term “C₁₋₄alkoxy-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-O—C₁₋₄alkyl.

As used herein, the term “C₁₋₄alkoxy-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-O—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkoxy-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-O—C₁₋₄alkyl)₂.

As used herein, the term “C₁₋₄alkoxy-C₁₋₄alkyl-amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-NH—C₁₋₄alkyl-O—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkoxy-C₁₋₄alkyl)₂-amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-N(C₁₋₄alkyl-O—C₁₋₄alkyl)₂.

As used herein, the term “(C₁₋₄alkoxy-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-N(C₁₋₄alkyl)(C₁₋₄alkyl-O—C₁₋₄alkyl).

As used herein, the term “C₁₋₄alkoxy-C₁₋₄alkyl-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-NH—C₁₋₄alkyl-O—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkoxy-C₁₋₄alkyl)₂-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl-O—C₁₋₄alkyl)₂.

As used herein, the term “(C₁₋₄alkoxy-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl)(C₁₋₄alkyl-O—C₁₋₄alkyl).

As used herein, the term “C₁₋₄alkoxy-carbonyl” refers to a radical of the formula: —C(O)—O—C₁₋₄alkyl.

As used herein, the term “C₁₋₄alkoxy-carbonyl-C₂₋₈alkenyl” refers to a radical of the formula: —C₂₋₈alkenyl-C(O)—O—C₁₋₄alkyl.

As used herein, the term “C₁₋₄alkoxy-carbonyl-amino” refers to a radical of the formula: —NH—C(O)—O—C₁₋₄alkyl.

As used herein, the term “C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl)₂.

As used herein, the term “C₁₋₄alkyl-amino-C₂₋₈alkenyl” refers to a radical of the formula: —C₂₋₈alkenyl-NH—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkyl)₂-amino-C₂₋₈alkenyl” refers to a radical of the formula: —C₂₋₈alkenyl-N(C₁₋₄alkyl)₂.

As used herein, the term “C₁₋₄alkyl-amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-NH—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkyl)₂-amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-N(C₁₋₄alkyl)₂.

As used herein, the term “C₁₋₄alkyl-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-NH—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkyl)₂-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl)₂.

As used herein, the term “C₁₋₄alkyl-amino-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-NH—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkyl)₂-amino-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-N(C₁₋₄alkyl)₂.

As used herein, the term “(C₁₋₄alkyl-amino-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-NH—C₁₋₄alkyl)₂.

As used herein, the term “[(C₁₋₄alkyl)₂-amino-C₁₋₄alky]₂-amino” refers to a radical of the formula: —N[C₁₋₄alkyl-N(C₁₋₄alkyl)_(2]2.)

As used herein, the term “(C₁₋₄alkyl-amino-C₁₋₄alkyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(C₁₋₄alkyl-NH—C₁₋₄alkyl).

As used herein, the term “[(C₁₋₄alkyl)₂-amino-C₁₋₄alkyl](C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)[C₁₋₄alkyl-N(C₁₋₄alkyl)₂].

As used herein, the term “C₁₋₄alkyl-amino-C₂₋₈alkynyl” refers to a radical of the formula: —C₂₋₈alkynyl-NH—C₁₋₄alkyl.

As used herein, the term “(C₁₋₄alkyl)₂-amino-C₂₋₈alkynyl” refers to a radical of the formula: —C₂₋₈alkynyl-N(C₁₋₄alkyl)₂.

As used herein, the term “C₁₋₄alkyl-carbonyl” refers to a radical of the formula: —C(O)—C₁₋₄alkyl.

As used herein, the term “C₁₋₄alkyl-carbonyl-amino” refers to a radical of the formula: —NH—C(O)—C₁₋₄alkyl.

As used herein, the term “C₁₋₄alkyl-thio” refers to a radical of the formula: —S—C₁₋₄alkyl.

As used herein, the term “amino-C₂₋₈alkenyl” refers to a radical of the formula: —C₂₋₈alkenyl-NH₂.

As used herein, the term “amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-NH₂.

As used herein, the term “amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-NH₂.

As used herein, the term “amino-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-NH₂.

As used herein, the term “(amino-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-NH₂)₂.

As used herein, the term “(amino-C₁₋₄alkyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(C₁₋₄alkyl-NH₂).

As used herein, the term “amino-C₂₋₈alkynyl” refers to a radical of the formula: —C₂₋₈alkynyl-NH₂.

As used herein, the term “aryl-C₁₋₄alkoxy-carbonyl” refers to a radical of the formula: —C(O)—O—C₁₋₄alkyl-aryl.

As used herein, the term “aryl-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-aryl.

As used herein, the term “aryl-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-aryl.

As used herein, the term “(aryl-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-aryl)₂.

As used herein, the term “(aryl-C₁₋₄alkyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(C₁₋₄alkyl-aryl).

As used herein, the term “aryl-C₁₋₄alkyl-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-NH—C₁₋₄alkyl-aryl.

As used herein, the term “(aryl-C₁₋₄alkyl)₂-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl-aryl)₂.

As used herein, the term “(aryl-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl)(C₁₋₄alkyl-aryl).

As used herein, the term “aryl-amino” refers to a radical of the formula: —NH-aryl.

As used herein, the term “aryl-amino-carbonyl” refers to a radical of the formula: —C(O)—NH-aryl.

As used herein, the term “aryl-sulfonyloxy-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-O—SO₂-aryl.

As used herein, the term “benzoxy-carbonyl” refers to a radical of the formula: —C(O)—O—CH₂-phenyl.

As used herein, the term “C₃₋₁₄cycloalkyl-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-C₃₋₁₄cycloalkyl.

As used herein, the term “C₃₋₁₄cycloalkyl-amino” refers to a radical of the formula: —NH—C₃₋₁₄cycloalkyl.

As used herein, the term “C₃₋₁₄cycloalkyl-oxy” refers to a radical of the formula: —O—C₃₋₁₄cycloalkyl.

As used herein, the term “deutero-C₁₋₄alkyl,” refers to a radical of the formula: —C₁₋₄alkyl-deutero, wherein C₁₋₄alkyl is partially or completely substituted with one or more deuterium atoms where allowed by available valences.

As used herein, the term “halo” or “halogen” generally refers to a halogen atom radical, including fluoro, chloro, bromo and iodo.

As used herein, the term “halo-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-halo, wherein C₁₋₄alkyl is partially or completely substituted with one or more halogen atoms where allowed by available valences.

As used herein, the term “halo-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-halo, wherein C₁₋₄alkyl is partially or completely substituted with one or more halogen atoms where allowed by available valences.

As used herein, the term “halo-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-halo.

As used herein, the term “(halo-C₁₋₄alkyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(C₁₋₄alkyl-halo).

As used herein, the term “(halo-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-halo)₂.

As used herein, the term “heteroaryl-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-heteroaryl.

As used herein, the term “heteroaryl-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-heteroaryl.

As used herein, the term “heteroaryl-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-heteroaryl.

As used herein, the term “(heteroaryl-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-heteroaryl)₂.

As used herein, the term “(heteroaryl-C₁₋₄alkyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(C₁₋₄alkyl-heteroaryl).

As used herein, the term “heteroaryl-C₁₋₄alkyl-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-NH—C₁₋₄alkyl-heteroaryl.

As used herein, the term “(heteroaryl-C₁₋₄alkyl)₂-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl-heteroaryl)₂.

As used herein, the term “(heteroaryl-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl)(C₁₋₄alkyl-heteroaryl).

As used herein, the term “heteroaryl-amino” refers to a radical of the formula: —NH-heteroaryl.

As used herein, the term “heterocyclyl-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-heterocyclyl.

As used herein, the term “heterocyclyl-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-heterocyclyl.

As used herein, the term “heterocyclyl-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-heterocyclyl.

As used herein, the term “(heterocyclyl-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-heterocyclyl)₂.

As used herein, the term “(heterocyclyl-C₁₋₄alkyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(C₁₋₄alkyl-heterocyclyl).

As used herein, the term “heterocyclyl-C₁₋₄alkyl-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-NH—C₁₋₄alkyl-heterocyclyl.

As used herein, the term “(heterocyclyl-C₁₋₄alkyl)₂-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl-heterocyclyl)₂.

As used herein, the term “(heterocyclyl-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl)(C₁₋₄alkyl-heterocyclyl).

As used herein, the term “heterocyclyl-amino” refers to a radical of the formula: —NH-heterocyclyl.

As used herein, the term “(heterocyclyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(heterocyclyl).

As used herein, the term “heterocyclyl-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-NH-heterocyclyl.

As used herein, the term “heterocyclyl-carbonyl” refers to a radical of the formula: —C(O)-heterocyclyl.

As used herein, the term “heterocyclyl-carbonyl-oxy” refers to a radical of the formula: —O—C(O)-heterocyclyl.

As used herein, the term “heterocyclyl-oxy” refers to a radical of the formula: —O-heterocyclyl.

As used herein, the term “hydroxy” refers to a radical of the formula: —OH.

As used herein, the term “hydroxy-C₁₋₄alkoxy-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-O—C₁₋₄alkyl-OH.

As used herein, the term “hydroxy-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-OH, wherein C₁₋₄alkyl is partially or completely substituted with one or more hydroxy radicals where allowed by available valences.

As used herein, the term “hydroxy-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-OH.

As used herein, the term “(hydroxy-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-OH)₂.

As used herein, the term “(hydroxy-C₁₋₄alkyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(C₁₋₄alkyl-OH).

As used herein, the term “hydroxy-C₁₋₄alkyl-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-NH—C₁₋₄alkyl-OH.

As used herein, the term “(hydroxy-C₁₋₄alkyl)₂-amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl-OH)₂.

As used herein, the term “(hydroxy-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkyl” refers to a radical of the formula: —C₁₋₄alkyl-N(C₁₋₄alkyl)(C₁₋₄alkyl-OH).

As used herein, the term “hydroxy-C₁₋₄alkyl-amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-NH—C₁₋₄alkyl-OH.

As used herein, the term “(hydroxy-C₁₋₄alkyl)₂-amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-N(C₁₋₄alkyl-OH)₂.

As used herein, the term “(hydroxy-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkoxy” refers to a radical of the formula: —O—C₁₋₄alkyl-N(C₁₋₄alkyl)(C₁₋₄alkyl-OH).

As used herein, the term “hydroxy-C₁₋₄alkyl-amino-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-NH—C₁₋₄alkyl-OH.

As used herein, the term “(hydroxy-C₁₋₄alkyl-amino-C₁₋₄alkyl)₂-amino” refers to a radical of the formula: —N(C₁₋₄alkyl-NH—C₁₋₄alkyl-OH)₂.

As used herein, the term “(hydroxy-C₁₋₄alkyl)₂-amino-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-N(C₁₋₄alkyl-OH)₂.

As used herein, the term “(hydroxy-C₁₋₄alkyl-amino-C₁₋₄alkyl)(C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)(C₁₋₄alkyl-NH—C₁₋₄alkyl-OH).

As used herein, the term “[(hydroxy-C₁₋₄alkyl)₂-amino-C₁₋₄alkyl](C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)[C₁₋₄alkyl-N(C₁₋₄alkyl-OH)_(2].)

As used herein, the term “(hydroxy-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkyl-amino” refers to a radical of the formula: —NH—C₁₋₄alkyl-N(C₁₋₄alkyl,C₁₋₄alkyl-OH).

As used herein, the term “[(hydroxy-C₁₋₄alkyl)(C₁₋₄alkyl)amino-C₁₋₄alkyl](C₁₋₄alkyl)amino” refers to a radical of the formula: —N(C₁₋₄alkyl)[C₁₋₄alkyl-N(C₁₋₄alkyl)(C₁₋₄alkyl-OH)].

As used herein, the term “substituent” means positional variables on the atoms of a core molecule that are substituted at a designated atom position, replacing one or more hydrogens on the designated atom, provided that the designated atom's normal valency is not exceeded, and that the substitution results in a stable compound. Combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. A person of ordinary skill in the art should note that any carbon as well as heteroatom with valences that appear to be unsatisfied as described or shown herein is assumed to have a sufficient number of hydrogen atom(s) to satisfy the valences described or shown. In certain instances one or more substituents having a double bond (e.g., “oxo” or “═O”) as the point of attachment may be described, shown or listed herein within a substituent group, wherein the structure may only show a single bond as the point of attachment to the core structure of Formula (I). A person of ordinary skill in the art would understand that, while only a single bond is shown, a double bond is intended for those substituents.

As used herein, the term “and the like,” with reference to the definitions of chemical terms provided herein, means that variations in chemical structures that could be expected by one skilled in the art include, without limitation, isomers (including chain, branching or positional structural isomers), hydration of ring systems (including saturation or partial unsaturation of monocyclic, bicyclic or polycyclic ring structures) and all other variations where allowed by available valences which result in a stable compound.

For the purposes of this description, where one or more substituent variables for a compound of Formula (I) or a form thereof encompass functionalities incorporated into a compound of Formula (I), each functionality appearing at any location within the disclosed compound may be independently selected, and as appropriate, independently and/or optionally substituted.

As used herein, the terms “independently selected,” or “each selected” refer to functional variables in a substituent list that may occur more than once on the structure of Formula (I), the pattern of substitution at each occurrence is independent of the pattern at any other occurrence. Further, the use of a generic substituent variable on any formula or structure for a compound described herein is understood to include the replacement of the generic substituent with species substituents that are included within the particular genus, e.g., aryl may be replaced with phenyl or naphthalenyl and the like, and that the resulting compound is to be included within the scope of the compounds described herein.

As used herein, the terms “each instance of” or “in each instance, when present,” when used preceding a phrase such as “. . . C₃₋₁₄cycloalkyl, C₃₋₁₄cycloalkyl-C₁₋₄alkyl, aryl, aryl-C₁₋₄alkyl, heteroaryl, heteroaryl-C₁₋₄alkyl, heterocyclyl and heterocyclyl-C₁₋₄alkyl,” are intended to refer to the C₃₋₁₄cycloalkyl, aryl, heteroaryl and heterocyclyl ring systems when each are present either alone or as a substituent.

As used herein, the term “optionally substituted” means optional substitution with the specified substituent variables, groups, radicals or moieties.

Compound Forms

As used herein, the term “form” means a compound of Formula (I) having a form selected from the group consisting of a free acid, free base, prodrug, salt, hydrate, solvate, clathrate, isotopologue, racemate, enantiomer, diastereomer, stereoisomer, polymorph and tautomer form thereof.

In certain aspects described herein, the form of the compound of Formula (I) is a free acid, free base or salt thereof.

In certain aspects described herein, the form of the compound of Formula (I) is a salt thereof.

In certain aspects described herein, the form of the compound of Formula (I) is an isotopologue thereof.

In certain aspects described herein, the form of the compound of Formula (I) is a stereoisomer, racemate, enantiomer or diastereomer thereof.

In certain aspects described herein, the form of the compound of Formula (I) is a tautomer thereof.

In certain aspects described herein, the form of the compound of Formula (I) is a pharmaceutically acceptable form.

In certain aspects described herein, the compound of Formula (I) or a form thereof is isolated for use.

As used herein, the term “isolated” means the physical state of a compound of Formula (I) or a form thereof after being isolated and/or purified from a synthetic process (e.g., from a reaction mixture) or natural source or combination thereof according to an isolation or purification process or processes described herein or which are well known to the skilled artisan (e.g., chromatography, recrystallization and the like) in sufficient purity to be characterized by standard analytical techniques described herein or well known to the skilled artisan.

As used herein, the term “protected” means that a functional group in a compound of Formula (I) or a form thereof is in a form modified to preclude undesired side reactions at the protected site when the compound is subjected to a reaction. Suitable protecting groups will be recognized by those with ordinary skill in the art as well as by reference to standard textbooks such as, for example, T. W. Greene et al, Protective Groups in organic Synthesis (1991), Wiley, New York. Such functional groups include hydroxy, phenol, amino and carboxylic acid. Suitable protecting groups for hydroxy or phenol include trialkylsilyl or diarylalkylsilyl (e.g., t-butyldimethylsilyl, t-butyldiphenylsilyl or trimethylsilyl), tetrahydropyranyl, benzyl, substituted benzyl, methyl, methoxymethanol, and the like. Suitable protecting groups for amino, amidino and guanidino include t-butoxycarbonyl, benzyloxycarbonyl, and the like. Suitable protecting groups for carboxylic acid include alkyl, aryl or arylalkyl esters. In certain instances, the protecting group may also be a polymer resin, such as a Wang resin or a 2-chlorotrityl-chloride resin. Protecting groups may be added or removed in accordance with standard techniques, which are well-known to those skilled in the art and as described herein. It will also be appreciated by those skilled in the art, although such protected derivatives of compounds described herein may not possess pharmacological activity as such, they may be administered to a subject and thereafter metabolized in the body to form compounds described herein which are pharmacologically active. Such derivatives may therefore be described as “prodrugs”. All prodrugs of compounds described herein are included within the scope of the use described herein.

As used herein, the term “prodrug” means a form of an instant compound (e.g., a drug precursor) that is transformed in vivo to yield an active compound of Formula (I) or a form thereof. The transformation may occur by various mechanisms (e.g., by metabolic and/or non-metabolic chemical processes), such as, for example, by hydrolysis and/or metabolism in blood, liver and/or other organs and tissues. A discussion of the use of prodrugs is provided by T. Higuchi and W. Stella, “Pro-drugs as Novel Delivery Systems,” Vol. 14 of the A.C.S. Symposium Series, and in Bioreversible Carriers in Drug Design, ed. Edward B. Roche, American Pharmaceutical Association and Pergamon Press, 1987.

In one example, when a compound of Formula (I) or a form thereof contains a carboxylic acid functional group, a prodrug can comprise an ester formed by the replacement of the hydrogen atom of the acid group with a functional group such as alkyl and the like. In another example, when a compound of Formula (I) or a form thereof contains a hydroxyl functional group, a prodrug form can be prepared by replacing the hydrogen atom of the hydroxyl with another functional group such as alkyl, alkylcarbonyl or a phosphonate ester and the like. In another example, when a compound of Formula (I) or a form thereof contains an amine functional group, a prodrug form can be prepared by replacing one or more amine hydrogen atoms with a functional group such as alkyl or substituted carbonyl. Pharmaceutically acceptable prodrugs of compounds of Formula (I) or a form thereof include those compounds substituted with one or more of the following groups: carboxylic acid esters, sulfonate esters, amino acid esters, phosphonate esters and mono-, di- or triphosphate esters or alkyl substituents, where appropriate. As described herein, it is understood by a person of ordinary skill in the art that one or more of such substituents may be used to provide a compound of Formula (I) or a form thereof as a prodrug.

One or more compounds described herein may exist in unsolvated as well as solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like, and the description herein is intended to embrace both solvated and unsolvated forms.

As used herein, the term “solvate” means a physical association of a compound described herein with one or more solvent molecules. This physical association involves varying degrees of ionic and covalent bonding, including hydrogen bonding. In certain instances the solvate will be capable of isolation, for example when one or more solvent molecules are incorporated in the crystal lattice of the crystalline solid. As used herein, “solvate” encompasses both solution-phase and isolatable solvates. Non-limiting examples of suitable solvates include ethanolates, methanolates, and the like.

As used herein, the term “hydrate” means a solvate wherein the solvent molecule is water.

The compounds of Formula (I) can form salts, which are intended to be included within the scope of this description. Reference to a compound of Formula (I) or a form thereof herein is understood to include reference to salt forms thereof, unless otherwise indicated. The term “salt(s)”, as employed herein, denotes acidic salts formed with inorganic and/or organic acids, as well as basic salts formed with inorganic and/or organic bases. In addition, when a compound of Formula (I) or a form thereof contains both a basic moiety, such as, without limitation an amine moiety, and an acidic moiety, such as, but not limited to a carboxylic acid, zwitterions (“inner salts”) may be formed and are included within the term “salt(s)” as used herein.

The term “pharmaceutically acceptable salt(s)”, as used herein, means those salts of compounds described herein that are safe and effective (i.e., non-toxic, physiologically acceptable) for use in mammals and that possess biological activity, although other salts are also useful. Salts of the compounds of the Formula (I) may be formed, for example, by reacting a compound of Formula (I) or a form thereof with an amount of acid or base, such as an equivalent amount, in a medium such as one in which the salt precipitates or in an aqueous medium followed by lyophilization.

Pharmaceutically acceptable salts include one or more salts of acidic or basic groups present in compounds described herein. Particular aspects of acid addition salts include, and are not limited to, acetate, ascorbate, benzoate, benzenesulfonate, bisulfate, bitartrate, borate, bromide, butyrate, chloride, citrate, camphorate, camphorsulfonate, ethanesulfonate, formate, fumarate, gentisinate, gluconate, glucaronate, glutamate, iodide, isonicotinate, lactate, maleate, methanesulfonate, naphthalenesulfonate, nitrate, oxalate, pamoate, pantothenate, phosphate, propionate, saccharate, salicylate, succinate, sulfate, tartrate, thiocyanate, toluenesulfonate (also known as tosylate), trifluoroacetate salts and the like. Certain particular aspects of acid addition salts include chloride or dichloride.

Additionally, acids which are generally considered suitable for the formation of pharmaceutically useful salts from basic pharmaceutical compounds are discussed, for example, by P. Stahl et al, Camille G. (eds.) Handbook of Pharmaceutical Salts. Properties, Selection and Use. (2002) Zurich: Wiley-VCH; S. Berge et al, Journal of Pharmaceutical Sciences (1977) 66(1) 1-19; P. Gould, International J. of Pharmaceutics (1986) 33, 201-217; Anderson et al, The Practice of Medicinal Chemistry (1996), Academic Press, New York; and in The Orange Book (Food & Drug Administration, Washington, D.C. on their website). These disclosures are incorporated herein by reference thereto.

Suitable basic salts include, but are not limited to, aluminum, ammonium, calcium, lithium, magnesium, potassium, sodium and zinc salts.

All such acid salts and base salts are intended to be included within the scope of pharmaceutically acceptable salts as described herein. In addition, all such acid and base salts are considered equivalent to the free forms of the corresponding compounds for purposes of this description.

Compounds of Formula (I) and forms thereof, may further exist in a tautomeric form. All such tautomeric forms are contemplated and intended to be included within the scope of the compounds of Formula (I) or a form thereof as described herein.

The compounds of Formula (I) or a form thereof may contain asymmetric or chiral centers, and, therefore, exist in different stereoisomeric forms. The present description is intended to include all stereoisomeric forms of the compounds of Formula (I) as well as mixtures thereof, including racemic mixtures.

The compounds described herein may include one or more chiral centers, and as such may exist as racemic mixtures (R/S) or as substantially pure enantiomers and diastereomers. The compounds may also exist as substantially pure (R) or (S) enantiomers (when one chiral center is present). In one particular aspect, the compounds described herein are (S) isomers and may exist as enantiomerically pure compositions substantially comprising only the (S) isomer. In another particular aspect, the compounds described herein are (R) isomers and may exist as enantiomerically pure compositions substantially comprising only the (R) isomer. As one of skill in the art will recognize, when more than one chiral center is present, the compounds described herein may also exist as a (R,R), (R,S), (S,R) or (S,S) isomer, as defined by IUPAC Nomenclature Recommendations.

As used herein, the term “substantially pure” refers to compounds consisting substantially of a single isomer in an amount greater than or equal to 90%, in an amount greater than or equal to 92%, in an amount greater than or equal to 95%, in an amount greater than or equal to 98%, in an amount greater than or equal to 99%, or in an amount equal to 100% of the single isomer.

In one aspect of the description, a compound of Formula (I) or a form thereof is a substantially pure (S) enantiomer form present in an amount greater than or equal to 90%, in an amount greater than or equal to 92%, in an amount greater than or equal to 95%, in an amount greater than or equal to 98%, in an amount greater than or equal to 99%, or in an amount equal to 100%.

In one aspect of the description, a compound of Formula (I) or a form thereof is a substantially pure (R) enantiomer form present in an amount greater than or equal to 90%, in an amount greater than or equal to 92%, in an amount greater than or equal to 95%, in an amount greater than or equal to 98%, in an amount greater than or equal to 99%, or in an amount equal to 100%.

As used herein, a “racemate” is any mixture of isometric forms that are not “enantiomerically pure”, including mixtures such as, without limitation, in a ratio of about 50/50, about 60/40, about 70/30, or about 80/20.

In addition, the present description embraces all geometric and positional isomers. For example, if a compound of Formula (I) or a form thereof incorporates a double bond or a fused ring, both the cis- and trans-forms, as well as mixtures, are embraced within the scope of the description. Diastereomeric mixtures can be separated into their individual diastereomers on the basis of their physical chemical differences by methods well known to those skilled in the art, such as, for example, by chromatography and/or fractional crystallization. Enantiomers can be separated by use of chiral HPLC column or other chromatographic methods known to those skilled in the art. Enantiomers can also be separated by converting the enantiomeric mixture into a diastereomeric mixture by reaction with an appropriate optically active compound (e.g., chiral auxiliary such as a chiral alcohol or Mosher's acid chloride), separating the diastereomers and converting (e.g., hydrolyzing) the individual diastereomers to the corresponding pure enantiomers. Also, some of the compounds of Formula (I) may be atropisomers (e.g., substituted biaryls) and are considered as part of this description.

All stereoisomers (for example, geometric isomers, optical isomers and the like) of the present compounds (including those of the salts, solvates, esters and prodrugs of the compounds as well as the salts, solvates and esters of the prodrugs), such as those which may exist due to asymmetric carbons on various substituents, including enantiomeric forms (which may exist even in the absence of asymmetric carbons), rotameric forms, atropisomers, and diastereomeric forms, are contemplated within the scope of this description, as are positional isomers (such as, for example, 4-pyridyl and 3-pyridyl). Individual stereoisomers of the compounds described herein may, for example, be substantially free of other isomers, or may be present in a racemic mixture, as described supra.

The use of the terms “salt”, “solvate”, “ester”, “prodrug” and the like, is intended to equally apply to the salt, solvate, ester and prodrug of enantiomers, stereoisomers, rotamers, tautomers, positional isomers, racemates or isotopologues of the instant compounds.

The term “isotopologue” refers to isotopically-enriched compounds described herein which are identical to those recited herein, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Examples of isotopes that can be incorporated into compounds described herein include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, fluorine and chlorine, such as ²H, ³H, ¹³C, ¹⁴C, ¹⁵N, ¹⁸O, ¹⁷O, ³¹P, ³²P, ³⁵, ¹⁸F, ³⁵Cl and ³⁶Cl, respectively, each of which are also within the scope of this description.

Certain isotopically-enriched compounds described herein (e.g., those labeled with ³H and ¹⁴C) are useful in compound and/or substrate tissue distribution assays. Tritiated (i.e., ³H) and carbon-14 (i.e., ¹⁴C) isotopes are particularly preferred for their ease of preparation and detectability. Further, substitution with heavier isotopes such as deuterium (i.e., ²H) may afford certain therapeutic advantages resulting from greater metabolic stability (e.g., increased in vivo half-life or reduced dosage requirements) and hence may be preferred in some circumstances.

Polymorphic crystalline and amorphous forms of the compounds of Formula (I) and of the salts, solvates, hydrates, esters and prodrugs of the compounds of Formula (I) are further intended to be included in the present description.

Compound Uses

In accordance with the intended scope of the present description, aspects of the present description include compounds that have been identified and have been demonstrated to be useful in selectively preventing, treating or ameliorating HD and have been provided for use for preventing, treating or ameliorating HD.

An aspect of the present description includes a method for preventing, treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound of Formula (I) or a form thereof.

An aspect of the present description includes a method for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound of Formula (I) or a form thereof.

An aspect of the present description includes a method for preventing HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound of Formula (I) or a form thereof.

An aspect of the present description includes a method for treating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound of Formula (I) or a form thereof.

An aspect of the present description includes a method for ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound of Formula (I) or a form thereof.

Another aspect of the present description includes a method for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of a compound salt of Formula (I) or a form thereof.

An aspect of the present description includes a method for use of a compound of Formula (I) or a form or composition thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form or composition thereof.

Another aspect of the present description includes a method for use of a compound salt of Formula (I) or a form or composition thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound salt of Formula (I) or a form thereof.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form thereof.

Another aspect of the present description includes a use for a compound salt of Formula (I) or a form thereof for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound salt of Formula (I) or a form thereof.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in the manufacture of a medicament for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the medicament.

Another aspect of the present description includes a use for a compound salt of Formula (I) or a form thereof in the manufacture of a medicament for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the medicament.

An aspect of the present description includes in vitro or in vivo use of the compound of Formula (I) or a form thereof having activity toward HD.

An aspect of the present description includes a use of the compound of Formula (I) or a form thereof in a combination therapy to provide additive or synergistic activity, thus enabling the development of a combination product for treating or ameliorating HD.

Another aspect of the present description includes a combination therapy comprising compounds described herein in combination with one or more known drugs or one or more known therapies may be used to treat HD regardless of whether HD is responsive to the known drug.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in a combination product with one or more therapeutic agents for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form thereof in combination with an effective amount of the one or more agents.

Another aspect of the present description includes a use for a compound salt of Formula (I) or a form thereof in a combination product with one or more therapeutic agents for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound salt of Formula (I) or a form thereof in combination with an effective amount of the one or more agents.

In an aspect of a use or method provided herein, compounds of Formula (I) or a form thereof used in combination with one or more additional agents can be administered to a subject or contacted with a subject or patient cell(s) prior to, concurrently with, or subsequent to administering to the subject or patient or contacting the cell with an additional agent(s). A compound(s) of Formula (I) or a form thereof and an additional agent(s) can be administered to a subject or contacted with a cell in single composition or different compositions. In a specific aspect, a compound(s) of Formula (I) or a form thereof is used in combination with gene therapy to inhibit HTT expression (using, e.g., viral delivery vectors) or the administration of another small molecule HTT inhibitor. In another specific aspect, a compound(s) of Formula (I) or a form thereof are used in combination with cell replacement using differentiated non-mutant HTT stem cells. In another specific aspect, a compound(s) of Formula (I) or a form thereof are used in combination with cell replacement using differentiated HTT stem cells.

In one aspect, provided herein is the use of compounds of Formula (I) or a form thereof in combination with supportive standard of care therapies, including palliative care.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in the preparation of a kit for treating or ameliorating HD in a subject in need thereof comprising, the compound of Formula (I) or a form thereof and instructions for administering an effective amount of the compound of Formula (I) or a form thereof.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in the preparation of a kit for treating or ameliorating HD in a subject in need thereof comprising, the compound of Formula (I) or a form thereof and instructions for administering an effective amount of the compound of Formula (I) or a form thereof; and optionally, for administering to the subject an effective amount of the compound of Formula (I) or a form thereof in a combination product with an effective amount of one or more therapeutic agents.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in the preparation of a kit for treating or ameliorating HD in a subject in need thereof comprising, the compound of Formula (I) or a form thereof and instructions for administering an effective amount of the compound of Formula (I) or a form thereof; and optionally, for administering to the subject an effective amount of the compound of Formula (I) or a form thereof in a combination product with an effective amount of the one or more therapeutic agents; and optionally, for administering to the subject an effective amount of the compound of Formula (I) or a form thereof in a combination product with an effective amount of the one or more therapeutic agents in a combination therapy with a standard of care supportive therapy, wherein the standard of care supportive therapy is palliative care.

In one respect, for each of such aspects, the subject is treatment naive. In another respect, for each of such aspects, the subject is not treatment naive.

As used herein, the term “preventing” refers to keeping a disease, disorder or condition from occurring in a subject that may be predisposed to the disease, disorder and/or condition but has not yet been diagnosed as having the disease, disorder and/or condition.

As used herein, the term “treating” refers to inhibiting the progression of a disease, disorder or condition in a subject already exhibiting the symptoms of the disease, disorder and/or condition, i.e., arresting the development of a disease, disorder and/or condition that has already affected the subject.

As used herein, the term “ameliorating” refers to relieving the symptoms of a disease, disorder or condition in a subject already exhibiting the symptoms of the disease, disorder and/or condition, i.e., causing regression of the disease, disorder and/or condition that has already affected the subject.

As used herein, the term “subject” refers to an animal or any living organism having sensation and the power of voluntary movement, and which requires oxygen and organic food.

Nonlimiting examples include members of the human, primate, equine, porcine, bovine, murine, rattus, canine and feline specie. In certain aspects, the subject is a mammal or a warm-blooded vertebrate animal. In other aspects, the subject is a human. As used herein, the term “patient” may be used interchangeably with “subject” and “human”.

As used herein, the terms “effective amount” or “therapeutically effective amount” mean an amount of compound of Formula (I) or a form, composition or medicament thereof that achieves a target plasma concentration that is effective in treating or ameliorating HD as described herein and thus producing the desired therapeutic, ameliorative, inhibitory or preventative effect in a subject in need thereof. In one aspect, the effective amount may be the amount required to treat HD in a subject or patient, more specifically, in a human.

In another aspect, the concentration-biological effect relationships observed with regard to a compound of Formula (I) or a form thereof indicate a target plasma concentration ranging from approximately 0.001 μg/mL to approximately 50 μg/mL, from approximately 0.01 μg/mL to approximately 20 μg/mL, from approximately 0.05 μg/mL to approximately 10 μg/mL, or from approximately 0.1 μg/mL to approximately 5 μg/mL. To achieve such plasma concentrations, the compounds described herein may be administered at doses that vary, such as, for example, without limitation, from 1.0 ng to 10,000 mg.

In one aspect, the dose administered to achieve an effective target plasma concentration may be administered based upon subject or patient specific factors, wherein the doses administered on a weight basis may be in the range of from about 0.001 mg/kg/day to about 3500 mg/kg/day, or about 0.001 mg/kg/day to about 3000 mg/kg/day, or about 0.001 mg/kg/day to about 2500 mg/kg/day, or about 0.001 mg/kg/day to about 2000 mg/kg/day, or about 0.001 mg/kg/day to about 1500 mg/kg/day, or about 0.001 mg/kg/day to about 1000 mg/kg/day, or about 0.001 mg/kg/day to about 500 mg/kg/day, or about 0.001 mg/kg/day to about 250 mg/kg/day, or about 0.001 mg/kg/day to about 200 mg/kg/day, or about 0.001 mg/kg/day to about 150 mg/kg/day, or about 0.001 mg/kg/day to about 100 mg/kg/day, or about 0.001 mg/kg/day to about 75 mg/kg/day, or about 0.001 mg/kg/day to about 50 mg/kg/day, or about 0.001 mg/kg/day to about 25 mg/kg/day, or about 0.001 mg/kg/day to about 10 mg/kg/day, or about 0.001 mg/kg/day to about 5 mg/kg/day, or about 0.001 mg/kg/day to about 1 mg/kg/day, or about 0.001 mg/kg/day to about 0.5 mg/kg/day, or about 0.001 mg/kg/day to about 0.1 mg/kg/day, or from about 0.01 mg/kg/day to about 3500 mg/kg/day, or about 0.01 mg/kg/day to about 3000 mg/kg/day, or about 0.01 mg/kg/day to about 2500 mg/kg/day, or about 0.01 mg/kg/day to about 2000 mg/kg/day, or about 0.01 mg/kg/day to about 1500 mg/kg/day, or about 0.01 mg/kg/day to about 1000 mg/kg/day, or about 0.01 mg/kg/day to about 500 mg/kg/day, or about 0.01 mg/kg/day to about 250 mg/kg/day, or about 0.01 mg/kg/day to about 200 mg/kg/day, or about 0.01 mg/kg/day to about 150 mg/kg/day, or about 0.01 mg/kg/day to about 100 mg/kg/day, or about 0.01 mg/kg/day to about 75 mg/kg/day, or about 0.01 mg/kg/day to about 50 mg/kg/day, or about 0.01 mg/kg/day to about 25 mg/kg/day, or about 0.01 mg/kg/day to about 10 mg/kg/day, or about 0.01 mg/kg/day to about 5 mg/kg/day, or about 0.01 mg/kg/day to about 1 mg/kg/day, or about 0.01 mg/kg/day to about 0.5 mg/kg/day, or about 0.01 mg/kg/day to about 0.1 mg/kg/day, or from about 0.1 mg/kg/day to about 3500 mg/kg/day, or about 0.1 mg/kg/day to about 3000 mg/kg/day, or about 0.1 mg/kg/day to about 2500 mg/kg/day, or about 0.1 mg/kg/day to about 2000 mg/kg/day, or about 0.1 mg/kg/day to about 1500 mg/kg/day, or about 0.1 mg/kg/day to about 1000 mg/kg/day, or about 0.1 mg/kg/day to about 500 mg/kg/day, or about 0.1 mg/kg/day to about 250 mg/kg/day, or about 0.1 mg/kg/day to about 200 mg/kg/day, or about 0.1 mg/kg/day to about 150 mg/kg/day, or about 0.1 mg/kg/day to about 100 mg/kg/day, or about 0.1 mg/kg/day to about 75 mg/kg/day, or about 0.1 mg/kg/day to about 50 mg/kg/day, or about 0.1 mg/kg/day to about 25 mg/kg/day, or about 0.1 mg/kg/day to about 10 mg/kg/day, or about 0.1 mg/kg/day to about 5 mg/kg/day, or about 0.1 mg/kg/day to about 1 mg/kg/day, or about 0.1 mg/kg/day to about 0.5 mg/kg/day.

Effective amounts for a given subject may be determined by routine experimentation that is within the skill and judgment of a clinician or a practitioner skilled in the art in light of factors related to the subject. Dosage and administration may be adjusted to provide sufficient levels of the active agent(s) or to maintain the desired effect. Factors which may be taken into account include genetic screening, severity of the disease state, status of disease progression, general health of the subject, ethnicity, age, weight, gender, diet, time of day and frequency of administration, drug combination(s), reaction sensitivities, experience with other therapies, and tolerance/response to therapy.

The dose administered to achieve an effective target plasma concentration may be orally administered once (once in approximately a 24 hour period; i.e., “q.d.”), twice (once in approximately a 12 hour period; i.e., “b.i.d.” or “q.12h”), thrice (once in approximately an 8 hour period; i.e., “t.i.d.” or “q.8h”), or four times (once in approximately a 6 hour period; i.e., “q.d.s.”, “q.i.d.” or “q.6h”) daily.

In certain aspects, the dose administered to achieve an effective target plasma concentration may also be administered in a single, divided, or continuous dose for a patient or subject having a weight in a range of between about 40 to about 200 kg (which dose may be adjusted for patients or subjects above or below this range, particularly children under 40 kg).

The typical adult subject is expected to have a median weight in a range of about 70 kg. Long-acting pharmaceutical compositions may be administered every 2, 3 or 4 days, once every week, or once every two weeks depending on half-life and clearance rate of the particular formulation.

The compounds and compositions described herein may be administered to the subject via any drug delivery route known in the art. Nonlimiting examples include oral, ocular, rectal, buccal, topical, nasal, sublingual, transdermal, subcutaneous, intramuscular, intraveneous (bolus and infusion), intracerebral, and pulmonary routes of administration.

In another aspect, the dose administered may be adjusted based upon a dosage form described herein formulated for delivery at about 0.02, 0.025, 0.03, 0.05, 0.06, 0.075, 0.08, 0.09, 0.10, 0.20, 0.25, 0.30, 0.50, 0.60, 0.75, 0.80, 0.90, 1.0, 1.10, 1.20, 1.25, 1.50, 1.75, 2.0, 3.0, 5.0, 10,20,30,40,50, 100, 150,200,250,300,400,500, 1000, 1500,2000,2500,3000 or 4000 mg/day.

For any compound, the effective amount can be estimated initially either in cell culture assays or in relevant animal models, such as a mouse, guinea pig, chimpanzee, marmoset or tamarin animal model. Relevant animal models may also be used to determine the appropriate concentration range and route of administration. Such information can then be used to determine useful doses and routes for administration in humans. Therapeutic efficacy and toxicity may be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., ED₅₀ (the dose therapeutically effective in 50% of the population) and LD₅₀ (the dose lethal to 50% of the population). The dose ratio between therapeutic and toxic effects is therapeutic index, and can be expressed as the ratio, LD₅₀/ED₅₀. In certain aspects, the effective amount is such that a large therapeutic index is achieved. In further particular aspects, the dosage is within a range of circulating concentrations that include an ED₅₀ with little or no toxicity. The dosage may vary within this range depending upon the dosage form employed, sensitivity of the patient, and the route of administration.

In one aspect, provided herein are methods for modulating the amount of HTT (huntingtin protein), comprising contacting a human cell with a compound of Formula (I) or a form thereof. In a specific aspect, provided herein are methods for modulating the amount of HTT, comprising contacting a human cell with a compound of Formula (I) or a form thereof that modulates the expression of HTT. The human cell can be contacted with a compound of Formula (I) or a form thereof in vitro, or in vivo, e.g., in a non-human animal or in a human. In a specific aspect, the human cell is from or in a human. In another specific aspect, the human cell is from or in a human with HD. In another specific aspect, the human cell is from or in a human with HD, caused by a CAG repeat in the Htt gene, resulting in a loss of HTT expression and/or function. In another aspect, the human cell is from a human with HD. In another aspect, the human cell is in a human with HD. In one aspect, the compound is a form of the compound of Formula (I).

In a specific aspect, provided herein is a method for enhancing the inhibition of mutant HTT transcribed from the Htt gene, comprising contacting a human cell with a compound of Formula (I) or a form thereof. The human cell can be contacted with a compound of Formula (I) or a form thereof in vitro, or in vivo, e.g., in a non-human animal or in a human. In a specific aspect, the human cell is from or in a human. In another specific aspect, the human cell is from or in a human with HD. In another specific aspect, the human cell is from or in a human with HD, caused by a CAG repeat in the Htt gene, resulting in a loss of wild-type “normal” HTT expression and/or function. In another aspect, the human cell is from a human with HD. In another aspect, the human cell is in a human with HD. In one aspect, the compound is a form of the compound of Formula (I).

In another aspect, provided herein is a method for modulating the inhibition of mutant HTT transcribed from the Htt gene, comprising administering to a non-human animal model for HD a compound of Formula (I) or a form thereof. In a specific aspect, provided herein is a method for modulating the inhibition of mutant HTT transcribed from the Htt gene, comprising administering to a non-human animal model for HD a compound of Formula (I) or a form thereof. In a specific aspect, the compound is a form of the compound of Formula (I).

In another aspect, provided herein is a method for decreasing the amount of mutant HTT, comprising contacting a human cell with a compound of Formula (I) or a form thereof. In a specific aspect, provided herein is a method for decreasing the amount of mutant HTT, comprising contacting a human cell with a compound of Formula (I) that inhibits the transcription of mutant HTT (huntingtin mRNA) from the Htt gene. In another specific aspect, provided herein is a method for decreasing the amount of HTT, comprising contacting a human cell with a compound of Formula (I) that inhibits the expression of mutant HTT transcribed from the Htt gene. The human cell can be contacted with a compound of Formula (I) or a form thereof in vitro, or in vivo, e.g., in a non-human animal or in a human. In a specific aspect, the human cell is from or in a human. In another specific aspect, the human cell is from or in a human with HD. In another specific aspect, the human cell is from or in a human with HD, caused by a CAG repeat in the Htt gene, resulting in a loss of HTT expression and/or function. In another aspect, the human cell is from a human with HD. In another aspect, the human cell is in a human with HD. In one aspect, the compound is a form of the compound of Formula (I).

In certain aspects, treating or ameliorating HD with a compound of Formula (I) or a form thereof (alone or in combination with an additional agent) has a therapeutic effect and/or beneficial effect. In a specific aspect, treating HD with a compound of Formula (I) or a form thereof (alone or in combination with an additional agent) results in one, two or more of the following effects: (i) reduces or ameliorates the severity of HD; (ii) delays onset of HD; (iii) inhibits the progression of HD; (iv) reduces hospitalization of a subject; (v) reduces hospitalization length for a subject; (vi) increases the survival of a subject; (vii) improves the quality of life for a subject; (viii) reduces the number of symptoms associated with HD; (ix) reduces or ameliorates the severity of a symptom(s) associated with HD; (x) reduces the duration of a symptom associated with HD; (xi) prevents the recurrence of a symptom associated with HD; (xii) inhibits the development or onset of a symptom of HD; and/or (xiii) inhibits of the progression of a symptom associated with HD.

Metabolites

Another aspect included within the scope of the present description are the use of in vivo metabolic products of the compounds described herein. Such products may result, for example, from the oxidation, reduction, hydrolysis, amidation, esterification and the like of the administered compound, primarily due to enzymatic processes. Accordingly, the description includes the use of compounds produced by a process comprising contacting a compound described herein with a mammalian tissue or a mammal for a period of time sufficient to yield a metabolic product thereof.

Such products typically are identified by preparing a radio-labeled isotopologue (e.g., ¹⁴C or ³H) of a compound described herein, administering the radio-labeled compound in a detectable dose (e.g., greater than about 0.5 mg/kg) to a mammal such as a rat, mouse, guinea pig, dog, monkey or human, allowing sufficient time for metabolism to occur (typically about 30 seconds to about 30 hours), and identifying the metabolic conversion products from urine, bile, blood or other biological samples. The conversion products are easily isolated since they are “radiolabeled” by virtue of being isotopically-enriched (others are isolated by the use of antibodies capable of binding epitopes surviving in the metabolite). The metabolite structures are determined in conventional fashion, e.g., by MS or NMR analysis. In general, analysis of metabolites may be done in the same way as conventional drug metabolism studies well-known to those skilled in the art. The conversion products, so long as they are not otherwise found in vivo, are useful in diagnostic assays for therapeutic dosing of the compounds described herein even if they possess no biological activity of their own.

Pharmaceutical Compositions

In accordance with the intended scope of the present description, aspects of the present description include compounds that have been identified and have been demonstrated to be useful in selectively preventing, treating or ameliorating HD and have been provided for use as one or more pharmaceutical compositions for preventing, treating or ameliorating HD.

An aspect of the present description includes a use for a compound of Formula (I) or a form thereof in the preparation of a pharmaceutical composition for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form thereof in admixture with one or more pharmaceutically acceptable excipients.

An aspect of the present description includes a use for a pharmaceutical composition of the compound of Formula (I) or a form thereof in the preparation of a kit for treating or ameliorating HD in a subject in need thereof comprising, the pharmaceutical composition of the compound of Formula (I) or a form thereof and instructions for administering the pharmaceutical composition.

As used herein, the term “composition” means a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts.

The pharmaceutical composition may be formulated to achieve a physiologically compatible pH, ranging from about pH 3 to about pH 11. In certain aspects, the pharmaceutical composition is formulated to achieve a pH of from about pH 3 to about pH 7. In other aspects, the pharmaceutical composition is formulated to achieve a pH of from about pH 5 to about pH 8.

The term “pharmaceutically acceptable excipient” refers to an excipient for administration of a pharmaceutical agent, such as the compounds described herein. The term refers to any pharmaceutical excipient that may be administered without undue toxicity. Pharmaceutically acceptable excipients may be determined in part by the particular composition being administered, as well as by the particular mode of administration and/or dosage form. Nonlimiting examples of pharmaceutically acceptable excipients include carriers, solvents, stabilizers, adjuvants, diluents, etc. Accordingly, there exists a wide variety of suitable formulations of pharmaceutical compositions for the instant compounds described herein (see, e.g., Remington's Pharmaceutical Sciences).

Suitable excipients may be carrier molecules that include large, slowly metabolized macromolecules such as proteins, polysaccharides, polylactic acids, polyglycolic acids, polymeric amino acids, amino acid copolymers, and inactive antibodies. Other exemplary excipients include antioxidants such as ascorbic acid; chelating agents such as EDTA; carbohydrates such as dextrin, hydroxyalkylcellulose, hydroxyalkylmethylcellulose (e.g., hydroxypropylmethylcellulose, also known as HPMC), stearic acid; liquids such as oils, water, saline, glycerol and ethanol; wetting or emulsifying agents; pH buffering substances; and the like. Liposomes are also included within the definition of pharmaceutically acceptable excipients.

The pharmaceutical compositions described herein may be formulated in any form suitable for the intended use described herein. Suitable formulations for oral administration include solids, liquid solutions, emulsions and suspensions, while suitable inhalable formulations for pulmonary administration include liquids and powders. Alternative formulations include syrups, creams, ointments, tablets, and lyophilized solids which can be reconstituted with a physiologically compatible solvent prior to administration.

When intended for oral use for example, tablets, troches, lozenges, aqueous or oil suspensions, non-aqueous solutions, dispersible powders or granules (including micronized particles or nanoparticles), emulsions, hard or soft capsules, syrups or elixirs may be prepared. Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions, and such compositions may contain one or more agents including sweetening agents, flavoring agents, coloring agents, and preserving agents, in order to provide a palatable preparation.

Pharmaceutically acceptable excipients suitable for use in conjunction with tablets include, for example, inert diluents, such as celluloses, calcium or sodium carbonate, lactose, calcium or sodium phosphate; disintegrating agents, such as croscarmellose sodium, cross-linked povidone, maize starch, or alginic acid; binding agents, such as povidone, starch, gelatin or acacia; and lubricating agents, such as magnesium stearate, stearic acid, or talc. Tablets may be uncoated or may be coated by known techniques including microencapsulation to delay disintegration and adsorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate alone or with a wax may be employed.

Formulations for oral use may be also presented as hard gelatin capsules where the active ingredient is mixed with an inert solid diluent, for example celluloses, lactose, calcium phosphate, or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with non-aqueous or oil medium, such as glycerin, propylene glycol, polyethylene glycol, peanut oil, liquid paraffin, or olive oil.

In other aspects, pharmaceutical compositions described herein may be formulated as suspensions comprising a compound of Formula (I) or a form thereof in admixture with one or more pharmaceutically acceptable excipients suitable for the manufacture of a suspension. In yet other aspects, pharmaceutical compositions described herein may be formulated as dispersible powders and granules suitable for preparation of a suspension by the addition of one or more excipients.

Excipients suitable for use in connection with suspensions include suspending agents, such as sodium carboxymethylcellulose, methylcellulose, hydroxypropyl methylcelluose, sodium alginate, polyvinylpyrrolidone, gum tragacanth, gum acacia, dispersing or wetting agents such as a naturally occurring phosphatide (e.g., lecithin), a condensation product of an alkylene oxide with a fatty acid (e.g., polyoxyethylene stearate), a condensation product of ethylene oxide with a long chain aliphatic alcohol (e.g., heptadecaethyleneoxycethanol), a condensation product of ethylene oxide with a partial ester derived from a fatty acid and a hexitol anhydride (e.g., polyoxyethylene sorbitan monooleate); and thickening agents, such as carbomer, beeswax, hard paraffin, or cetyl alcohol. The suspensions may also contain one or more preservatives such as acetic acid, methyl and/or n-propyl p-hydroxy-benzoate; one or more coloring agents; one or more flavoring agents; and one or more sweetening agents such as sucrose or saccharin.

The pharmaceutical compositions described herein may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil, such as olive oil or arachis oil, a mineral oil, such as liquid paraffin, or a mixture of these. Suitable emulsifying agents include naturally-occurring gums, such as gum acacia and gum tragacanth; naturally occurring phosphatides, such as soybean lecithin, esters or partial esters derived from fatty acids; hexitol anhydrides, such as sorbitan monooleate; and condensation products of these partial esters with ethylene oxide, such as polyoxyethylene sorbitan monooleate. The emulsion may also contain sweetening and flavoring agents. Syrups and elixirs may be formulated with sweetening agents, such as glycerol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative, a flavoring or a coloring agent.

Additionally, the pharmaceutical compositions described herein may be in the form of a sterile injectable preparation, such as a sterile injectable aqueous emulsion or oleaginous suspension. Such emulsion or suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, such as a solution in 1,2-propanediol. The sterile injectable preparation may also be prepared as a lyophilized powder. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile fixed oils may be employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono- or di-glycerides. In addition, fatty acids such as oleic acid may likewise be used in the preparation of injectables.

The compounds described herein may be substantially insoluble in water and sparingly soluble in most pharmaceutically acceptable protic solvents and vegetable oils, but generally soluble in medium-chain fatty acids (e.g., caprylic and capric acids) or triglycerides and in propylene glycol esters of medium-chain fatty acids. Thus, contemplated in the description are compounds which have been modified by substitutions or additions of chemical or biochemical moieties which make them more suitable for delivery (e.g., increase solubility, bioactivity, palatability, decrease adverse reactions, etc.), for example by esterification, glycosylation, PEGylation, etc.

In certain aspects, the compound described herein is formulated for oral administration in a lipid-based composition suitable for low solubility compounds. Lipid-based formulations can generally enhance the oral bioavailability of such compounds. As such, pharmaceutical compositions described herein may comprise a effective amount of a compound of Formula (I) or a form thereof, together with at least one pharmaceutically acceptable excipient selected from medium chain fatty acids or propylene glycol esters thereof (e.g., propylene glycol esters of edible fatty acids such as caprylic and capric fatty acids) and pharmaceutically acceptable surfactants, such as polysorbate 20 or 80 (also referred to as Tween® 20 or Tween® 80, respectively) or polyoxyl 40 hydrogenated castor oil.

In other aspects, the bioavailability of low solubility compounds may be enhanced using particle size optimization techniques including the preparation of nanoparticles or nanosuspensions using techniques known to those skilled in the art. The compound forms present in such preparations include amorphous, partially amorphous, partially crystalline or crystalline forms.

In alternative aspects, the pharmaceutical composition may further comprise one or more aqueous solubility enhancer(s), such as a cyclodextrin. Nonlimiting examples of cyclodextrin include hydroxypropyl, hydroxyethyl, glucosyl, maltosyl and maltotriosyl derivatives of α-, β-, and γ-cyclodextrin, and hydroxypropyl-β-cyclodextrin (HPBC). In certain aspects, the pharmaceutical composition further comprises HPBC in a range of from about 0.1% to about 20%, from about 1% to about 15%, or from about 2.5% to about 10%. The amount of solubility enhancer employed may depend on the amount of the compound in the composition.

Preparation of Compounds General Synthetic Methods

As disclosed herein, general methods for preparing the compounds of Formula (I) or a form thereof as described herein are available via standard, well-known synthetic methodology. Many of the starting materials are commercially available or, when not available, can be prepared using the routes described below using techniques known to those skilled in the art. The synthetic schemes provided herein comprise multiple reaction steps, each of which is intended to stand on its own and can be carried out with or without any preceding or succeeding step(s). In other words, each of the individual reaction steps of the synthetic schemes provided herein in isolation is contemplated.

Scheme A

Compounds of Formula (I), wherein B is heterocyclyl, X is O, NH, or NR_(1b), and R_(1b) is C₁₋₄alkyl, may be prepared as described in Scheme A below.

Compound A1 (where W₁ and W₂ are independently bromine, chlorine and the like) is converted to Compound A2 by a nucleophilic substitution with a primary or secondary amine or an alcohol (BXH) in the presence of a suitable base (such as Et₃N and the like) in a suitable solvent (such as DMF and the like). Alternatively, Compound A1 is converted to Compound A2 via cross coupling with a primary or a secondary amine or an alcohol in the presence of a suitable catalyst (such as RuPhos Pd G2 and the like) and base (such as sodium tert-butoxide and the like) in an appropriate solvent such as 1,4-dioxane and the like). Compound A2 is converted to Compound A3 by a Suzuki coupling with an aryl- or heteroaryl-boronic acid (or pinacol boronic ester) in the presence of a catalyst (such as Pd(dppf)Cl₂ and the like) and base (such as aqueous K₂CO₃ and the like) in a suitable solvent (such as 1,4-dioxane and the like). Alternatively, Compound A2 is converted to Compound A3 by a Stille coupling with an aryl- or heteroaryl-stannane in the presence of a catalyst (such as Pd₂(dba)₃ and the like), a ligand (such as X-Phos and the like) and a base (such as CsF and the like) in a suitable solvent (such as 1,4-dioxane and the like). Any protecting groups may be removed upon treatment with a suitable reagent (such as HCl in dioxane for a Boc protecting group and the like) in a suitable solvent (such as dioxane and the like).

Scheme B

Compounds of Formula (I), wherein (R₃)_(n) is hydrogen, halogen, hydroxy, or C₁₋₄alkoxy, n is 0 or 1, R₃ is heterocyclyl, heteroaryl, or phenyl, B is heterocyclyl; X is O, NH or NR_(1b), and R_(1b) is C₁₋₄alkyl, may be prepared as described in Scheme B below.

Compound B1 (where W₁ and W₂ are independently bromine, chlorine and the like) is converted to Compound B3 by a Suzuki coupling with an aryl-boronic acid (or pinacol boronic ester) B2 (where W₃ is bromine, chlorine and the like; (R₃)_(n) is hydrogen, halogen, hydroxy, or C₁₋₄alkoxy, and n is 0 or 1; and PG is a protecting group such as MOM and the like) in the presence of a catalyst (such as Pd(dppf)Cl₂ and the like) and base (such as aqueous K₂CO₃ and the like) in a suitable solvent (such as 1,4-dioxane and the like). Compound B3 is converted to Compound B4 by a nucleophilic substitution with a primary or a secondary amine or an alcohol (BXH, where X is O, NH, or NR_(1b), and where R_(1b) is C₁₋₄alkyl) in the presence of a suitable base (such as Et₃N and the like) in a suitable solvent (such as DMF and the like). Alternatively, Compound B3 is converted to Compound B4 via cross coupling with a primary or a secondary amine or an alcohol in the presence of a suitable catalyst (such as RuPhos Pd G2 and the like) and base (such as sodium tert-butoxide and the like) in an appropriate solvent such as 1,4-dioxane and the like). Compound B4 is converted to Compound B5 by a Suzuki coupling with an aryl- or heteroaryl-boronic acid (or pinacol boronic ester) in the presence of a catalyst (such as Pd(dppf)Cl₂ and the like) and a base (such as aqueous K₂CO₃ and the like) in a suitable solvent (such as 1,4-dioxane and the like). Alternatively, Compound B4 is converted to Compound B5 by a Stille coupling with an aryl- or heteroaryl-stannane in the presence of a catalyst (such as Pd₂(dba)₃ and the like), a ligand (such as X-Phos and the like) and a base (such as CsF and the like) in a suitable solvent (such as 1,4-dioxane and the like). Alternatively, Compound B4 is converted to Compound B5 by treatment with pinacolatodiboron and a base (such as KOAc and the like) in the presence of a catalyst (such as Pd(dppf)Cl₂ and the like) in an appropriate solvent (such as 1,4-dioxane and the like), followed by addition of an aryl- or heteroaryl-halide. Alternatively, Compound B4 is converted to Compound B5 by a Buchwald-Hartwig coupling with a heteroaryl or amine in the presence of a catalyst (such as Pd₂(dba)₃ and the like), a ligand (such as tBuX-Phos and the like) and a base (such as K₃PO₄ and the like) in a suitable solvent (such as 1,4-dioxane and the like). Compound B5 is converted to Compound B6 upon treatment with conditions appropriate to the removal of the protecting groups (such as HCl in dioxane for a MOM protecting group) in a suitable solvent (such as dioxane and the like).

Scheme C

Following the general conditions described in General Scheme B, but reversing the order of steps 1 and 2, compound Cl can be converted to compound C6.

Specific Synthetic Examples

To describe in more detail and assist in understanding, the following non-limiting examples are offered to more fully illustrate the scope of compounds described herein and are not to be construed as specifically limiting the scope thereof. Such variations of the compounds described herein that may be now known or later developed, which would be within the purview of one skilled in the art to ascertain, are considered to fall within the scope of the compounds as described herein and hereinafter claimed. These examples illustrate the preparation of certain compounds. Those of skill in the art will understand that the techniques described in these examples represent techniques, as described by those of ordinary skill in the art, that function well in synthetic practice, and as such constitute preferred modes for the practice thereof. However, it should be appreciated that those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific methods that are disclosed and still obtain a like or similar result without departing from the spirit and scope of the present description.

Other than in the following examples of the embodied compounds, unless indicated to the contrary, all numbers expressing quantities of ingredients, reaction conditions, experimental data, and so forth used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, all such numbers represent approximations that may vary depending upon the desired properties sought to be obtained by a reaction or as a result of variable experimental conditions. Therefore, within an expected range of experimental reproducibility, the term “about” in the context of the resulting data, refers to a range for data provided that may vary according to a standard deviation from the mean. As well, for experimental results provided, the resulting data may be rounded up or down to present data consistently, without loss of significant figures. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of significant digits and rounding techniques used by those of skill in the art.

While the numerical ranges and parameters setting forth the broad scope of the present description are approximations, the numerical values set forth in the examples set forth below are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

The starting materials used in the examples provided are commercially available or can be prepared according to methods known to one skilled in the art or can be prepared by the proceedures disclosed herein.

Compound Examples

As used above, and throughout the present description, the following abbreviations, unless otherwise indicated, shall be understood to have the following meanings:

Abbreviation Meaning Δ heating (chemistry) or deletion (biology) AcOH or HOAc acetic acid Ar argon ACN or CH₃CN acetonitrile aq. aqueous atm atmosphere(s) BBr₃ boron tribromide B₂pin₂ bis(pinacolato)diboron Boc tert-butoxy-carbonyl t-Bu tert-butyl t-BuOK or KOtBu postassium tert-butoxide BuOH or n-BuOH n-butanol ° C. degrees Centigrade Celite ® or Celite diatomaceous earth d/h/hr/hrs/min/s day(d)/hour(h, hr or hrs)/minute(min)/second(s) DCM or CH₂Cl₂ dichloromethane DMF dimethylformamide DMSO dimethylsulfoxide EtOAc ethyl acetate EtOH ethanol Et₂O diethyl ether equiv equivalents H₂ hydrogen HBr hydrobromic acid HCl hydrochloric acid H₂SO₄ sulfuric acid K₂CO₃ potassium carbonate KOAc potassium acetate KOH potassium hydroxide LC/MS, LCMS or liquid chromatographic mass spectroscopy LC-MS LiOt-Bu lithium tert-butoxide LiOH lithium hydroxide mCPBA meta-chloroperoxybenzoic acid MeOH methanol MeSO₃H methanesulfonic acid MgSO₄ magnesium sulfate mL mililiter MOM methoxymethyl MS mass spectroscopy NEt₃ triethylamine NH₄Cl ammonium chloride NH₄OAc ammonium acetate Na₂CO₃ sodium carbonate NaH sodium hydride NaHCO₃ sodium bicarbonate NaOH sodium hydroxide Na₂SO₄ sodium sulfate N₂ nitrogen NH₄Cl ammoniuim chloride NMP N-methylpyrrolidone NMR nuclear magnetic resonance Pd palladium Pd/C palladium on carbon Pd₂(dba)₃ tris(dibenzylideneacetone)dipalladium(0) Pd(dppf)Cl₂ or [1,1′- Pd(dppf)Cl₂—CH₂Cl₂ bis(diphenylphosphino)ferrocene]dichloropalladium(II), complex with dichloromethane PhMe toluene Psi pounds per square inch pressure QPhos 1,2,3,4,5-pentaphenyl-1′-(di-tert-butylphosphino)ferrocene Rt or rt room temperature S-Phos, SPhos or Sphos 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl S-Phos G₂ chloro(2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′- biphenyl)(2′-amino-1,1′-biphenyl-2-yl) palladium(II) TBAF tetrabutylammonium fluoride TBS tert-butyldimethylsilyl TEA, Et₃N or NEt₃ triethylamine Tf trifluoromethane sulfonyl or triflate TFA trifluoroacetic acid THF tetrahydrofuran THP tetrahydropyranyl TIPS tiisopropylsilane TLC thin layer chromatography UPLC Ulta performance liquid chromatography

Preparation of Starting Material: 4-(3-(Methoxymethoxy)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole

Step 1: 2-Bromo-5-iodophenol (54.9 g, 184 mmol), was dissolved in DMF (240 mL) at 0° C. Sodium tert-pentoxide (2.5 M in THF, 90 mL, 230 mmol) was added dropwise. This was stirred at 0° C. for 15 minutes after addition was complete. Chloromethyl methyl ether (18 mL, 225 mmol) was added dropwise over 30 minutes. The mixture was warmed to ambient temperature and was stirred for 16 hours. The mixture was diluted with 1.5 L of H₂O and was extracted into 2×400 mL of EtOAc. The combined organic layers were washed with 300 mL of H₂O, and then with brine. The organic layer was dried over MgSO₄, filtered, and concentrated under vacuum. The residue was flushed through a silica plug using 0-10% CH₂Cl₂ in hexanes to yield 1-bromo-4-iodo-2-(methoxymethoxy)benzene (61 g, 97%) as a clear liquid.

¹H NMR (acetone-d₆): δ 7.56 (d, J=2 Hz, 1H), 7.38 (d, J=8 Hz, 1H), 7.33 (dd, J=8 Hz, 2 Hz, 1H), 5.35 (s, 2H), 3.50 (s, 3H).

Step 2: 1-Bromo-4-iodo-2-(methoxymethoxy)benzene (49 g, 143 mmol), 1-(tetrahydro-2H-pyran-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (48.4 g, 174 mmol), Pd(dppf)Cl₂-dichloromethane adduct (3.1 g, 3.6 mmol), dioxane (500 mL), and aqueous K₂CO₃ (1M, 350 mL, 350 mmol) were heated at 90° C. for 2 hours. The reaction mixture was then partitioned between H₂O and EtOAc. The organic layer was dried over MgSO₄, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography eluting with a EtOAc/hexanes gradient (20-50% EtOAc), followed by trituration with hexanes, yielding 4-(4-bromo-3-(methoxymethoxy)phenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole (40.4 g, 77% yield) as an off-white solid.

¹H NMR (acetone-d₆): δ 8.22 (s, 1H), 7.88 (s, 1H), 7.55 (d, J=8.5 Hz, 1H), 7.47 (d, J=2 Hz, 1H), 7.23 (dd, J=8.5 Hz, 2 Hz, 1H), 5.44 (dd, J=9.5 Hz, 2.5 Hz, 1H), 5.38 (s, 2H), 4.01 (m, 1H), 3.72 (m, 1H), 3.51 (s, 3H), 2.1-2.23 (m, 1H), 2.0-2.1 (m, 2H), 1.7-1.8 (m, 1H), 1.6-1.7 (m, 2H).

Step 3: A flask containing potassium acetate (22 g, 224 mmol) was pumped dry at 180° C. for 2 hours, and then was filled with argon. 4-(4-Bromo-3-(methoxymethoxy)phenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole (20 g, 54.5 mmol), Pd(dppf)Cl₂-dichloromethane adduct (1.22 g, 1.47 mmol), bis(pinacolato)diboron (20.8 g, 81.9 mmol), and dry toluene (200 mL) were added. The mixture was heated at 110° C. for 48 h. After cooling, the mixture was filtered through celite, followed by rinsing with ether. The filtrate was concentrated under vacuum, re-dissolved in ether, and was filtered again through celite to remove solid impurities. Purification by silica gel chromatography eluting with a gradient of EtOAc/hexanes (20-50% EtOAc) yielded 12 g of crude title product. The crude material was dissolved in 100 mL ether and was back-washed with 2×1.5 L of dilute aqueous NaHCO₃. The ether layer was washed with brine, dried over MgSO₄, and was filtered. The filtrate was concentrated to a glassy semi-solid. This material was hexane-triturated to yield 4-(3-(methoxymethoxy)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole as a white crystalline solid (7.05 g, 32% yield).

¹H NMR (acetone-d₆): δ 8.24 (s, 1H), 7.90 (s, 1H), 7.65 (d, J=8 Hz, 1H), 7.33 (d, J=1.5 Hz, 1H), 7.29 (dd, J=8 Hz, 1.5 Hz, 1H), 5.45 (dd, J=10 Hz, 2.5 Hz, 1H), 5.25 (s, 2H), 4.01 (m, 1H), 3.69-3.74 (m, 1H), 3.52 (s, 3H), 2.15-2.2 (m, 1H), 2.0-2.1 (m, 2H), 1.7-1.8 (m, 1H), 1.6-1.68 (m, 2H), 1.35 (s, 12H).

Using the procedure described, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Structure Data

MS m/z 345.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 7.94-8.03 (m, 1H), 7.84 (s, 1H), 7.64 (br d, J = 7.6 Hz, 1H), 7.25 (s, 1H), 7.20 (d, J = 7.3 Hz, 1H), 5.25 (s, 2H), 3.81-3.98 (m, 3H), 3.53 (s, 3H), 1.36 (s, 12H)

MS m/z 348.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.00 (s, 1H), 7.85 (s, 1H), 7.64 (br d, J = 7.6 Hz, 1H), 7.26 (s, 1H), 7.22 (d, J = 7.6 Hz, 1H), 5.26 (s, 2H), 4.86 (s, 3H), 1.37 (s, 12H)

MS m/z 349.2 [M − THP + H]⁺

MS m/z 316.6 [M + H]⁺

MS m/z 391.5 [M + H]⁺

MS m/z 391.5 [M + H]+; ¹H NMR (methanol-d₄) δ: 8.27-8.32 (m, 1H), 8.00-8.04 (m, 1H), 7.40- 7.52 (m, 2H), 5.42-5.56 (m, 1H), 4.08 (br d, J = 11.5 Hz, 1H), 3.77 (br t, J = 11.5 Hz, 1H), 2.12- 2.25 (m, 1H), 2.07 (br d, J = 11.0 Hz, 2H), 1.60- 1.86 (m, 3H), 1.38 (s, 12H)

MS m/z 391.5 [M + H]⁺

MS m/z 423.2, 425.2 [M + H]⁺

Preparation of Starting Material: 2-[4-Chloro-3-fluoro-2-(methoxymethoxy)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

Step 1: 6-Bromo-3-chloro-2-fluoro-phenol (900 mg, 4.0 mmol) was dissolved in DMF (4.5 mL) at 0′C. Sodium tert-pentoxide (2.5 Min THF, 2 mL, 5.0 mmol) was added dropwise, followed by dropwise addition of chloromethyl methyl ether (405 μL, 5.34 mmol) and the reaction was stirred overnight at room temperature. The reaction mixture was partitioned between water and EtOAc. The organic layer was washed with water, and then brine. The organic layer was dried over MgSO₄, filtered, and concentrated under vacuum. The residue was purified by silica gel chromatography eluting with a EtOAc/hexanes gradient (30-100% EtOAc) to yield 1-bromo-4-chloro-3-fluoro-2-(methoxymethoxy)benzene (1.01 g, 94% yield) as a clear oil. ¹H NMR (acetone-d₆) δ: 7.50 (d, J=9 Hz, 1H), 7.28 (t, J=8 Hz, 1H), 5.26 (s, 2H), 3.62 (s, 3H).

Step 2: A mixture of dry KOAc (1.5 g, 15 mmol), bis(pinacolato)diboron (1.02 g, 4.02 mmol), Pd(dppf)Cl₂—CH₂Cl₂ (90 mg, 0.108 mmol), and a solution of 1-bromo-4-chloro-3-fluoro-2-(methoxymethoxy)benzene (900 mg, 3.3 mmol) in toluene (12 mL) was purged with argon for 15 min. The mixture was heated at 110° C. for 16 h. Upon completion, the reaction was diluted with EtOAc and was filtered through celite. The filtrate was concentrated and purified by silica chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 5% MeOH) to yield 2-[4-chloro-3-fluoro-2-(methoxymethoxy)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (524 mg, 47% yield) as a light orange oil. ¹H NMR (acetone-d₆) δ: 7.49 (d, J=8 Hz, 1H), 7.29 (t, J=7 Hz, 1H), 5.16 (s, 2H), 3.58 (s, 3H), 1.37 (s, 12H).

Using the procedure described, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Structure Data

MS m/z 299.3, 301.3 [M + H]⁺

Preparation of Starting Material: N-(tert-Butyl)pyrrolidin-3-amine

Step 1: A dry vial was charged with 1-benzylpyrrolidin-3-one (4.0 g, 22.8 mmol), 2-methylpropan-2-amine (3.8 g, 52.0 mmol) and Ti(OiPr)₄ (6.0 mL, 20.2 mmol). The mixture was purged with N₂ for 15 min and then allowed to stir at room temperature for 2 h. The resulting (E)-1-benzyl-N-(tert-butyl)pyrrolidin-3-imine was used without further purification.

Step 2: To the mixture from step 1 was added dry methanol (40 mL) and the reaction was cooled to 0° C. in an ice bath. NaBH₄ (1.6 g, 42.3 mmol) was added slowly in portions (caution: very exothermic reaction). Once evolution of the gas subsided, the mixture was warmed to room temperature and stirred for 2h at room temperature. Upon completion, 0.1M NaOH solution (20 mL) was added to precipitate the titanium salts. The biphasic mixture was filtered through celite and washed with methanol. The solvent was removed under vacuum and the crude oil was purified by reverse phase chromatography using a acetonitrile/H₂O gradient (10%-100% acetonitrile) to afford 1-benzyl-N-(tert-butyl)pyrrolidine-3-amine (3.2 g, 60% yield) as a colorless oil.

Step 3: To an oven-dry round bottom flask containing palladium hydroxide on activated carbon (320 mg) was added 1-benzyl-N-(tert-butyl)pyrrolidine-3-amine (3.2 g, 13.8 mmol) dissolved in MeOH (20 mL). The mixture was sparged with H₂ for 5 minutes and a balloon of H₂ was placed on top of the flask and the reaction was stirred for 2 h at room temperature. The reaction mixture was filtered through celite, washed with MeOH and concentrated to afford N-(tert-butyl)pyrrolidin-3-amine (1.89 g, 96% yield) as a colorless oil which solidified upon standing.

¹H NMR (methanol-d₄) δ: 4.21 (dq, J=14.4, 7.0 Hz, 1H), 3.80 (dd, J=12.7, 8.0 Hz, 1H), 3.58-3.50 (m, 2H), 3.38-3.32 (m, 1H), 2.62-2.56 (m, 1H), 2.28-2.20 (m, 1H), 1.42 (s, 9H); 2 NHs not observed.

Example 1 Preparation of Compound 1

Step 1: A mixture of 2,5-dibromopyrazine (610 mg, 2.56 mmol) and N,2,2,6,6-pentamethylpiperidin-4-amine (480 mg, 2.8 mmol) in n-BuOH (3.0 mL) was stirred at 120° C. for 16 h until LCMS showed complete consumption of the starting material. The reaction mixture was cooled to room temperature, the solvent was evaporated under reduced pressure, and the residue was partitioned between EtOAc and aqueous saturated NaHCO₃. The organic layers were dried over Na₂SO₄, and the solvent was evaporated to provide 5-bromo-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (646 mg, 77%) as a yellowish solid. MS m/z 326.2, 328.2 [M+H]⁺.

Step 2: An oven-dried flask was equipped with a magnetic stir bar and charged with 5-bromo-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (570 mg, 1.74 mmol), tert-butyl(3-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenoxy)dimethylsilane (64 mg, 0.24 mmol, tetrakis(triphenylphosphine)palladium(0) (196 mg, 0.17 mmol), Na₂CO₃ (553 mg, 5.22 mmol). The flask was sealed with a rubber septum and then evacuated and backfilled with argon. Dioxane (10 mL) and water (2.5 mL) were added, and the reaction was heated to 90° C. for 16 h. The reaction mixture was cooled to room temperature, diluted with water (5 mL), and extracted with EtOAc. The organic layers were combined, dried over Na₂SO₄, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (0 to 30% MeOH) to afford 5-(4-((tert-butyldimethylsilyl)oxy)-2-methoxyphenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (529 mg, 63%) as a clear oil which partially solidified. MS m/z 485.6 [M+H]⁺.

Step 3: To a solution of 5-(4-((tert-butyldimethylsilyl)oxy)-2-methoxyphenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (529 mg, 1.09 mmol) in CH₂Cl₂ (3 mL) was added 4N HCl/dioxane (0.5 mL, 2.0 mmol) followed by MeOH (0.2 mL). The reaction mixture was stirred for 5 h at room temperate until LCMS showed complete consumption of the starting material. The solvent were removed under reduced pressure, and the residue was suspended in CH₂Cl₂(20 mL). 1,1,1-Trifluoro-N-phenyl-N-((trifluoromethyl)sulfonyl)methanesulfonamide (584 mg, 1.63 mmol) and trimethylamine (0.45 mL, 3.27 mmol) were added. The reaction mixture was stirred at room temperature for 16 h, then washed with water (2 mL) followed by brine. The organic layers were dried over Na₂SO₄, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (0 to 20% MeOH) to afford 3-methoxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl trifluoromethanesulfonate (402 mg, 73%) as a tan solid.

MS m/z 503.6 [M+H]⁺; ¹H NMR (acetone-d₆) δ: 8.77 (d, J=1.6 Hz, 1H), 8.25 (d, J=1.6 Hz, 1H), 8.06 (d, J=8.8 Hz, 1H), 7.26 (d, J=2.4 Hz, 1H), 7.15 (dd, J=8.7, 2.4 Hz, 1H), 5.32 (tt, J=13.2, 3.5 Hz, 1H), 4.05 (s, 3H), 3.00 (s, 3H), 2.08-2.10 (m, 2H), 1.84 (dd, J=13.2, 3.5 Hz, 2H), 1.63 (s, 6H), 1.55 (s, 6H); 1H not observed (NH).

Step 4: An oven-dried flask was equipped with a magnetic stir bar and charged with 3-methoxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl trifluoromethanesulfonate (180 mg, 0.35 mmol), 2-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (101 mg, 0.43 mmol, tetrakis(triphenylphosphine)palladium(0) (40 mg, 0.35 mmol), Na₂CO₃ (111 mg, 1.05 mmol). The flask was sealed with a rubber septum and then evacuated and backfilled with argon. Dioxane (6 mL) and water (1.5 mL) were added and the reaction was heated to 90° C. for 16 h. The reaction was cooled to room temperature, diluted with water (5 mL), and extracted with EtOAc. The organic layers were combined, dried over Na₂SO₄, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (0 to 30% MeOH) to afford 5-(2-methoxy-4-(2-methoxypyridin-4-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (86 mg, 53%) as a tan solid.

MS m/z 462.6 [M+H]⁺; ¹H NMR (methanol-d₄) δ: 8.69 (d, J=1.3 Hz, 1H), 8.20 (dd, J=5.4, 0.6 Hz, 1H), 8.12 (d, J=1.3 Hz, 1H), 7.82 (d, J=8.2 Hz, 1H), 7.41 (dd, J=8.2, 1.9 Hz, 1H), 7.38-7.40 (m, 1H), 7.32 (dd, J=5.4, 1.6 Hz, 1H), 7.13 (dd, J=1.6, 0.9 Hz, 1H), 5.15 (tt, J=12.6, 3.6 Hz, 1H), 4.00 (s, 3H), 3.99 (s, 3H), 3.01 (s, 3H), 1.67 (dd, J=12.6, 3.6 Hz, 2H), 1.56 (t, J=12.6 Hz, 2H), 1.39 (s, 6H), 1.25 (s, 6H); 1H not observed (NH).

Step 5: A solution of 5-(2-methoxy-4-(2-methoxypyridin-4-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (70 mg, 0.15 mmol) in 2 mL of dry CH₂Cl₂ was cooled in ice-water bath. Boron tribromide (1.0 M in CH₂Cl₂′1.5 mL, 1.5 mmol) was added, and the reaction mixture was stirred at room temperature for 16 hours. The reaction was quenched with 2 mL of MeOH, stirred for 30 min, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (2.5% NH₄0H) (0 to 30% MeOH/NH₄OH) to afford 4-(3-hydroxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl)pyridin-2-ol (33 mg, 51%) as a yellow solid.

MS m/z 434.6 [M+H]⁺; ¹H NMR (methanol-d₄) δ: 8.94 (d, J=1.6 Hz, 1H), 8.17 (d, J=1.3 Hz, 1H), 7.93-8.00 (m, 1H), 7.53 (dd, J=6.9, 0.9 Hz, 1H), 7.25-7.28 (m, 1H), 7.24 (d, J=1.9 Hz, 1H), 6.79-6.84 (m, 1H), 6.78 (dd, J=6.9, 1.9 Hz, 1H), 5.32-5.42 (m, 1H), 3.09 (s, 3H), 1.94 (d, J=7.9 Hz, 4H), 1.65 (s, 6H), 1.53 (s, 6H); 3Hs not observed (NH and 2 OHs).

Using the procedure described for Example 1, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Cpd Data 5 MS m/z 407.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.99 (d, J = 1.6 Hz, 1H), 8.31 (s, 1H), 8.15 (d, J = 1.2 Hz, 1H), 8.04 (d, J = 8.8 Hz, 1H), 7.79 (d, J = 1.2 Hz, 1H), 7.19 (s, 1H), 7.18 (d, J = 2.4 Hz, 1H), 7.10 (s, 1H), 4.93-5.01 (m, 1H), 2.94 (s, 3H), 1.48 (dd, J = 12.0, 3.6 Hz, 2H), 1.41 (t, J = 12.0 Hz, 2H), 1.24 (s, 6H), 1.08 (s, 6H); 2Hs not observed (NH and OH). 9 MS m/z 475.1 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.86 (s, 1H), 8.05 (s, 1H), 7.96 (s, 1H), 7.84 (d, J = 8.4 Hz, 1H), 6.96-7.02 (m, 2H), 5.11-5.23 (m, 1H), 3.01(s, 3H), 1.66 (dd, J = 12.8, 3.2 Hz, 2H), 1.55 (t, J = 12.8 Hz, 2H), 1.37 (s, 6H), 1.23 (s, 6H); 3Hs not observed (2NHs and OH). 12 MS m/z 421.1 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.85 (s, 1H), 8.04 (s, 1H), 7.82 (s, 1H), 7.68 (s, 1H), 7.26 (dd, J = 1.6, 8.4 Hz, 1H), 6.93 (d, J = 8.4 Hz, 1H), 5.13-5.26 (m, 1H), 3.00 (s, 3H), 2.42 (s, 3H), 1.51-1.75 (m, 4H), 1.38 (s, 6H), 1.25 (s, 6H); 3Hs not observed (2NHs and OH). 14 MS m/z 422.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.70 (d, J = 1.5 Hz, 1H), 7.91 (d, J = 1.5 Hz, 1H), 7.83 (d, J = 2.4 Hz, 1H), 7.74 (d, J = 9.5 Hz, 1H), 6.97-7.06 (m, 2H), 5.78 (d, J = 2.7 Hz, 1H), 5.05 (tt, J = 12.5, 3.4 Hz, 1H), 2.89 (s, 3H), 1.54 (dd, J = 12.5, 3.4 Hz, 2H), 1.44 (t, J = 12.5 Hz, 2H), 1.26 (s, 6H), 1.12 (s, 6H); 4Hs not observed (3NHs and OH). 18 MS m/z 448.4 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.94 (s, 1H), 8.08 (dd, J = 1.6, 8.8 Hz, 2H), 7.69 (d, J = 8.8 Hz, 1H), 7.53 (d, J = 8.8 Hz, 1H), 6.98 (d, J = 8.8 Hz, 1H), 6.71- 6.77 (m, 2H), 5.27-5.35 (m, 1H), 3.59 (s, 3H), 3.03 (s, 3H), 1.94 (t, J = 12.8 Hz, 2H), 1.86 (dd, J = 12.8, 3.6 Hz, 2H), 1.51 (s, 6H), 1.28 (s, 6H); 2Hs not observed (NH and OH). 27 MS m/z 421.4 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 12.39 (br. s., 1H), 8.95 (d, J = 1.6 Hz, 1H), 8.15 (s, 1H), 8.13 (d, J = 1.3 Hz, 1H), 7.88-7.92 (m, 1H), 7.87 (d, J = 0.9 Hz, 1H), 6.94-7.15 (m, 2H), 4.88-5.01 (m, 1H), 3.87 (s, 3H), 2.91-2.98 (m, 3H), 1.49 (dd, J = 12.1, 3.5 Hz, 2H), 1.41 (t, J = 12.1 Hz, 2H), 1.25 (s, 6H), 1.09 (s, 6H); 1H not observed (OH or NH). 28 MS m/z 424.5 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 9.02 (d, J = 1.3 Hz, 1H), 8.14 (d, J = 1.3 Hz, 1H), 8.10 (d, J = 0.9 Hz, 1H), 7.94-7.97 (m, 1H), 7.79 (d, J = 8.2 Hz, 1H), 7.23 (dd, J = 8.2, 1.6 Hz, 1H), 7.18 (d, J = 1.6 Hz, 1H), 5.28-5.41 (m, 1H), 3.12 (s, 3H), 1.92-2.05 (m, 4H), 1.61-1.68 (m, 6H), 1.56 (s, 6H); 2Hs not observed (OH and NH). 44 MS m/z 404.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.90 (s, 1H), 8.62 (d, J = 6.0 Hz, 2H), 8.39 (s, 1H), 7.98-8.02 (m, 2H), 7.70 (d, J = 6.0 Hz, 2H), 7.45 (d, J = 7.6 Hz, 1H), 7.31-7.34 (m, 2H), 4.30 (br s, 1H), 1.95-1.99 (m, 2H), 1.28-1.38 (m, 14H); 1H not observed (OH or NH) 45 MS m/z 404.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.88-8.91 (m, 2H), 8.56 (dd, J = 4.8, 1.2 Hz, 1H), 8.40 (s, 1H), 8.07-8.10 (m, 1H), 7.97-8.00 (m, 2H), 7.46-7.50 (m, 1H), 7.41 (d, J = 7.6 Hz, 1H), 7.23-7.26 (m, 2H), 4.27-4.31 (m, 1H), 1.94-1.98 (m, 2H), 1.27-1.37 (m, 14H); 1H not observed (OH or NH) 46 MS m/z 393.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.84 (s, 1H), 8.39 (s, 1H), 8.07 (s, 2H), 7.94 (s, 1H), 7.84 (d, J = 8.8 Hz, 1H), 7.35 (d, J = 7.2 Hz, 1H), 7.11-7.14 (m, 1H), 4.27-4.30 (m, 1H), 1.94-1.99 (m, 2H), 1.28-1.39 (m, 14H); 3Hs not observed (OH and NH) 54 MS m/z 407.3 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 12.00 (br s, 1H), 8.82 (s, 1H), 8.40 (br s, 1H), 8.14 (s, 1H), 7.92 (s, 1H), 7.82-7.86 (m, 2H), 7.31 (d, J = 7.6 Hz, 1H), 7.06- 7.08 (m, 2H), 4.25-4.28 (m, 1H), 3.86 (s, 3H), 1.91-1.96 (m, 2H), 1.24-1.35 (m, 14H)

Example 2 Preparation of Compound 26

Step 1: An oven-dried flask was equipped with a magnetic stir bar and charged with 5-bromo-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (255 mg, 0.97 mmol), 4-(3-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole (273 mg, 0.71 mmol), tetrakis(triphenylphosphine)palladium(0) (60 mg, 0.05 mmol), and Na₂CO₃ (160 mg, 1.5 mmol). The flask was sealed with a rubber septum and then evacuated and backfilled with argon. Dioxane (8 mL) and water (2 mL) were added, and the reaction was heated to 90° C. for 16 h. The reaction was cooled to room temperature, diluted with water (5 mL), and extracted with EtOAc. The combined organic layers were dried over Na₂SO₄ and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (0 to 30% MeOH) to afford 5-(2-methoxy-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (160 mg, 45%) as a yellow solid. MS m/z 505.6 [M+H]⁺.

Step 2: 5-(2-Methoxy-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (80 mg, 0.15 mmol) was suspended in dichloromethane (1 mL) at 0° C. Boron tribromide (1.5 mL, 1.5 mmol, 1M in CH₂C2) was added dropwise, and the mixture was stirred at 0° C. for 1 h and followed by room temperature for 16 hours. The mixture was quenched with MeOH (5 mL) and stirred for 30 min at room temperature. The solvents were removed under reduced pressure, and the residue was triturated with Et₂O (1 mL). The precipitate was collected by filtration and dried to provide 2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)-5-(1H-pyrazol-4-yl)phenol hydrobromide (42 mg, 65%) as a brownish solid.

MS m/z 407.5 [M+H]⁺; ¹H NMR (methanol-d₄) δ: 9.08 (d, J=1.6 Hz, 1H), 8.57 (s, 2H), 8.19 (d, J=1.6 Hz, 1H), 7.86 (d, J=8.2 Hz, 1H), 7.37 (dd, J=8.2, 1.6 Hz, 1H), 7.31 (d, J=1.6 Hz, 1H), 5.37 (tt, J=13.2, 4.1 Hz, 1H), 3.15 (s, 3H), 2.05 (t, J=13.2 Hz, 2H), 1.99 (dd, J=13.2, 4.1 Hz, 2H), 1.66 (s, 6H), 1.58 (s, 6H); 3Hs not observed (2 NHs and OH).

Using the procedure described for Example 2, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Cpd Data 19 MS m/z 407.6 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.86 (d, J = 1.2 Hz, 1H), 8.24 (d, J = 2.4 Hz, 1H), 8.05 (d, J = 1.2 Hz, 1H), 7.94 (d, J = 9.2 Hz, 1H), 7.74 (d, J = 1.5 Hz, 1H), 7.25-7.34 (m, 2H), 6.55 (dd, J = 2.4, 1.5 Hz, 1H), 5.18 (tt, J = 12.5, 3.7 Hz, 1H), 3.02 (s, 3H), 1.66 (dd, J = 12.5, 3.7 Hz, 2H), 1.55 (t, J = 12.5 Hz, 2H), 1.38 (s, 6H), 1.24 (s, 6H); 2Hs not observed (NH and OH). 22 MS m/z 425.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.81 (d, J = 1.5 Hz, 1H), 7.99-8.09 (m, 3H), 7.64 (d, J = 12.5 Hz, 1H), 7.17 (d, J = 6.7 Hz, 1H), 5.17 (tt, J = 12.5, 3.4 Hz, 1H), 3.01 (s, 3H), 1.65 (dd, J = 12.5, 3.4 Hz, 2H), 1.54 (t, J = 12.5 Hz, 2H), 1.37 (s, 6H), 1.23 (s, 6H); 3Hs not observed (OH and 2NHs). 52 MS m/z 379.4 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.74 (s, 1H), 7.90-7.97 (m, 2H), 7.88 (s, 1H), 7.74-7.76 (m, 1H), 7.11 (s, 2H), 3.87-3.94 (m, 1H), 3.64-3.77 (m, 2H), 3.46-3.55 (m, 1H), 3.18-3.25 (m, 1H), 2.33-2.44 (m, 1H), 1.86-1.98 (m, 1H), 1.22 (s, 9H); 3Hs not observed (2NHs and OH) 60 MS m/z 396.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.79 (s, 1H), 7.98 (s, 1H), 7.92-7.96 (m, 1H), 7.83 (s, 1H), 7.79 (d, J = 8.2 Hz, 1H), 7.04-7.15 (m, 2H), 3.92-4.01 (m, 1H), 3.84-3.92 (m, 1H), 3.72-3.80 (m, 1H), 3.50-3.59 (m, 1H), 3.36-3.41 (m, 1H), 2.40- 2.55 (m, 1H), 1.97-2.11 (m, 1H), 1.32 (s, 9H); 2Hs not observed (NH and OH) 62 MS m/z 393.3 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.94 (s, 1H), 8.09 (br d, J = 17.2 Hz, 2H), 7.93 (s, 1H), 7.82 (d, J = 7.9 Hz, 1H), 7.20 (d, J = 8.5 Hz, 1H), 7.13-7.17 (m, 1H), 4.29 (br d, J = 6.9 Hz, 1H), 4.11-4.19 (m, 1H), 3.98 (s, 3H), 3.87-3.92 (m, 1H), 3.75- 3.81 (m, 1H), 3.69 (br d, J = 8.2 Hz, 1H), 2.68 (br d, J = 6.0 Hz, 1H), 2.32-2.40 (m, 1H), 1.52 (s, 9H); 2Hs not observed (NH and OH)

Example 3 Preparation of Compound 13

Step 1: An oven-dried flask was equipped with a magnetic stir bar and charged with 5-bromo-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (150 mg, 0.46 mmol), 4-(2,3-difluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole (215 mg, 0.55 mmol), tetrakis(triphenylphosphine)palladium(0) (58 mg, 0.05 mmol), and Na₂CO₃ (146 mg, 1.38 mmol). The flask was sealed with a rubber septum and then evacuated and backfilled with argon. Dioxane (4 mL) and water (1 mL) were added, and the reaction was heated to 90° C. for 16 h. The reaction was cooled to room temperature, diluted with water (5 mL), and extracted with EtOAc. The combined organic layers were dried over Na₂SO₄ and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (0 to 30% MeOH) to afford 5-(2,3-difluoro-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (166 mg, 71%) as a brownish solid. MS m/z 511.6 [M+H]⁺.

Step 2:To 5-(2,3-difluoro-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (166 mg, 0.33 mmol) in CH₂Cl₂ (2 mL) was added 4N HCl/dioxane (0.17 mL, 0.66 mmol) followed by MeOH (0.2 mL). The reaction was stirred at room temperature for 2 h. The solvents were removed under reduced pressure, and the residue was triturated in Et₂O. The solid was filtered, washed with excess Et₂O and dried under vacuum to afford 5-(2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine hydrochloride (126 mg, 83%) as a yellow solid.

MS m/z 427.5 [M+H]⁺; ¹H NMR (methanol-d₄) δ: 8.65 (t, J=1.6 Hz, 1H), 8.47 (s, 2H), 8.35 (d, J=1.2 Hz, 1H), 7.80 (td, J=8.2, 1.8 Hz, 1H), 7.67 (td, J=8.2, 1.8 Hz, 1H), 5.36 (tt, J=12.0, 3.7 Hz, 1H), 3.13 (s, 3H), 1.98-2.04 (m, 2H), 1.95 (dd, J=13.7, 3.7 Hz, 2H), 1.66 (s, 6H), 1.56 (s, 6H); 2NHs not observed.

Using the procedure described for Example 3, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Cpd Data  4 MS m/z 459.3, 461.3 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.38 (d, J = 1.2 Hz, 1H), 8.03 (d, J = 1.2 Hz, 1H), 7.99 (br s, 2H), 7.64 (s, 1H), 7.60 (s, 1H), 5.01-5.14 (m, 1H), 2.92 (s, 3H), 1.56 (dd, J = 12.2, 3.1 Hz, 2H), 1.45 (t, J = 12.2 Hz, 2H), 1.26 (s, 6H), 1.13 (s, 6H); 2NHs not observed 11 MS m/z 423.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.51-4.63 (m, 1H), 8.19 (d, J = 1.2 Hz, 1H), 7.89 (s, 2H), 7.77 (d, J = 7.9 Hz, 1H), 7.26 (d, J = 12.5 Hz, 1H), 5.14-5.27 (m, 1H), 3.04 (s, 3H), 2.47 (s, 3H), 1.74 (dd, J = 13.4, 3.5 Hz, 2H), 1.66 (t, J = 13.4 Hz, 2H), 1.45 (s, 6H), 1.32 (s, 6H); 2NHs not observed. 15 MS m/z 427.6 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.60-8.63 (m, 1H), 8.21 (d, J = 1.5 Hz, 1H), 8.09-8.13 (m, 2H), 7.76 (dd, J = 12.2, 6.4 Hz, 1H), 7.58 (dd, J = 12.2, 6.4 Hz, 1H), 5.13-5.24 (m, 1H), 3.04 (s, 3H), 1.69 (dd, J = 12.5, 3.4 Hz, 2H), 1.59 (t, J = 12.5 Hz, 2H), 1.40 (s, 6H), 1.26 (s, 6H); 2NHs not observed. 16 MS m/z 409.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.63 (d, J = 1.2 Hz, 1H), 8.15 (d, J = 1.2 Hz, 1H), 8.08 (br. s., 2H), 7.68-7.80 (m, 3H), 5.11-5.25 (m, 1H), 3.03 (s, 3H), 1.70 (dd, J = 12.5, 3.4 Hz, 2H), 1.60 (t, J = 12.5 Hz, 2H), 1.41 (s, 6H), 1.28 (s, 6H); 2NHs not observed. 17 MS m/z 427.6 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.65 (d, J = 1.5 Hz, 1H), 8.15 (d, J = 1.5 Hz, 1H), 8.11 (s, 2H), 7.65 (d, J = 10.7 Hz, 2H), 5.18 (tt, J = 12.2, 3.4 Hz, 1H), 3.04 (s, 3H), 1.66 (dd, J = 12.2, 3.4 Hz, 2H), 1.57 (d, J = 12.2 Hz, 2H), 1.38 (s, 6H), 1.24 (s, 6H); 2NHs not observed. 23 MS m/z 443.4 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.60 (s, 1H), 8.20 (d, J = 1.2 Hz, 1H), 8.12 (s, 2H), 8.05 (d, J = 7.3 Hz, 1H), 7.49 (d, J = 12.2 Hz, 1H), 5.16 (s, 1H), 3.04 (s, 3H), 1.66 (dd, J = 12.4, 3.5 Hz, 2H), 1.55 (t, J = 12.5 Hz, 2H), 1.38 (s, 6H), 1.24 (s, 6H); 2NHs not observed. 24 MS m/z 434.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.57-8.67 (m, 1H), 8.38 (d, J = 7.6 Hz, 1H), 8.26 (s, 2H), 8.23 (d, J = 1.2 Hz, 1H), 7.63 (d, J = 12.5 Hz, 1H), 5.07-5.27 (m, 1H), 3.05 (s, 3H), 1.67 (dd, J = 12.2, 3.4 Hz, 2H), 1.57 (t, J = 12.4 Hz, 2H), 1.39 (s, 6H), 1.25 (s, 6H); 2NHs not observed. 41 MS m/z 441.3 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.62-8.67 (m, 1H), 8.30 (d, J = 1.5 Hz, 1H), 8.01 (s, 1H), 7.86-7.93 (m, 1H), 7.47-7.51 (m, 1H), 7.29 (s, 1H), 5.33-5.44 (m, 1H), 3.11 (s, 3H), 2.30 (s, 3H), 1.89-2.02 (m, 4H), 1.65 (s, 6H), 1.53 (s, 6H); 1NH not observed 42 MS m/z 442.5 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.88 (d, J = 2.4 Hz, 1H), 8.64-8.69 (m, 1H), 8.24 (d, J = 1.5 Hz, 1H), 8.03 (dd, J = 12.4, 6.6 Hz, 1H), 7.78 (dd, J = 11.3, 6.1 Hz, 1H), 5.14-5.26 (m, 1H), 3.06 (s, 3H), 2.49 (s, 3H), 1.65-1.75 (m, 2H), 1.53- 1.65 (m, 2H), 1.40 (s, 6H), 1.26 (s, 6H); 1NH not observed 63 MS m/z 399.4 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.59 (s, 1H), 8.28 (s, 2H), 8.26 (s, 1H), 7.74 (dd, J = 9.0, 7.8 Hz, 1H), 7.58 (t, J = 7.6 Hz, 1H), 4.24-4.33 (m, 1H), 4.12- 4.18 (m, 1H), 3.84-3.94 (m, 1H), 3.65-3.79 (m, 2H), 2.62-2.73 (m, 1H), 2.27-2.39 (m, 1H), 1.51 (s, 9H); 2NHs not observed 64 MS m/z 399.4 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.64 (s, 1H), 8.17 (s, 2H), 8.02-8.09 (m, 1H), 7.78 (dd, J = 12.1, 6.6 Hz, 1H), 7.60 (dd, J = 12.1, 6.3 Hz, 1H), 4.26 (br t, J = 6.9 Hz, 1H), 4.12 (dd, J = 11.4, 7.1 Hz, 1H), 3.83-3.90 (m, 1H), 3.63-3.71 (m, 2H), 2.62-2.71 (m, 1H), 2.23-2.34 (m, 1H), 1.50 (s, 9H); 2NHs not observed

Example 4 Preparation of Compound 2

Step 1: A mixture of 2,5-dibromopyrazine (610 mg, 2.56 mmol) and 2,2,6,6-tetramethylpiperidin-4-ol (480 mg, 2.8 mmol) in THF (10.0 mL) was cooled to 0° C., and 1.0 M t-BuOK in THF (9.1 mL, 9.1 mmol) was added dropwise. The reaction mixture was gradually warmed to room temperature and stirred for 16 h until LCMS showed complete consumption of the starting material. The solvent was evaporated under reduced pressure, and the residue was partitioned between EtOAc and water. The organic layers were dried over Na₂SO₄, the solvent was evaporated, and the residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (0 to 10% MeOH) to afford 2-bromo-5-((2,2,6,6-tetramethylpiperidin-4-yl)oxy)pyrazine (1.31 g, 55%) as a clear oil which solidified upon standing. MS m/z 313.1, 315.1 [M+H]⁺.

Step 2: An oven-dried flask was equipped with a magnetic stir bar and charged with 2-bromo-5-((2,2,6,6-tetramethylpiperidin-4-yl)oxy)pyrazine (367 mg, 1.17 mmol), 4-(3-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole (450 mg, 1.17 mmol, tetrakis(triphenylphosphine)palladium(0) (140 mg, 0.12 mmol), and Na₂CO₃ (372 mg, 3.51 mmol). The flask was sealed with a rubber septum and then evacuated and backfilled with argon. Dioxane (10 mL) and water (2.5 mL) were added, and the reaction was heated to 90° C. for 16 h. The reaction was cooled to room temperature, diluted with water (5 mL), and extracted with EtOAc. The combined organic layers were dried over Na₂SO₄ and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (0 to 30% MeOH) to afford 2-(2-methoxy-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)-5-((2,2,6,6-tetramethylpiperidin-4-yl)oxy)pyrazine (420 mg, 73%) as a tan solid.

MS m/z 492.6 [M+H]⁺; ¹H NMR (acetone-d₆) δ: 8.80 (d, J=1.6 Hz, 1H), 8.31 (d, J=0.6 Hz, 1H), 8.23 (d, J=1.6 Hz, 1H), 7.98 (d, J=0.6 Hz, 1H), 7.92 (d, J=7.9 Hz, 1H), 7.44 (d, J=1.6 Hz, 1H), 7.36 (dd, J=8.2, 1.6 Hz, 1H), 5.60 (tt, J=11.5, 3.9 Hz, 1H), 5.47 (dd, J=9.8, 2.2 Hz, 1H), 4.04 (s, 3H), 3.99-4.04 (m, 1H), 3.67-3.83 (m, 1H), 2.15-2.29 (m, 1H), 2.12 (dd, J=12.5, 3.9 Hz, 2H), 2.07-2.09 (m, 1H), 2.02-2.06 (m, 1H), 1.74-1.87 (m, 2H), 1.59-1.72 (m, 3H), 1.31 (s, 6H), 1.18 (s, 6H); 1H not observed (NH).

Step 3: An oven-dried microwave vial was equipped with a magnetic stir bar and charged with 2-(2-methoxy-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)-5-((2,2,6,6-tetramethylpiperidin-4-yl)oxy)pyrazine (278 mg, 0.56 mmol), benzenethiol (59 μL, 0.56 mmol) and K₂CO₃ (77 mg, 0.56 mmol). The vial was sealed and then evacuated and backfilled with argon. NMP (1.5 mL) was added, and the reaction was heated to 190° C. in a microwave reactor for 20 min. The reaction was cooled to room temperature, diluted with water (5 mL), and extracted with EtOAc. The combined organic layers were dried over Na₂SO₄ and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient CH₂Cl₂/MeOH (0 to 30% MeOH) to afford 5-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)-2-(5-((2,2,6,6-tetramethylpiperidin-4-yl)oxy)pyrazin-2-yl)phenol (227 mg, 84%) as a tan solid.

MS m/z 478.6 [M+H]⁺; ¹H NMR (acetone-d₆) δ:12.29 (s, 1H), 9.00 (d, J=1.3 Hz, 1H), 8.27 (d, J=0.6 Hz, 1H), 8.24 (br. s., 1H), 8.00 (d, J=8.2 Hz, 1H), 7.94 (d, J=0.9 Hz, 1H), 7.22-7.28 (m, 1H), 7.21 (d, J=1.9 Hz, 1H), 5.58-5.72 (m, 1H), 5.47 (dd, J=9.8, 2.2 Hz, 1H), 3.93-4.06 (m, 1H), 3.64-3.79 (m, 1H), 2.17-2.25 (m, 2H), 2.07-2.11 (m, 2H), 2.02-2.06 (m, 2H), 1.73-1.85 (m, 2H), 1.55-1.72 (m, 2H), 1.34 (s, 6H), 1.20 (s, 6H); 1H not observed (NH or OH).

Step 4: To a solution of 5-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)-2-(5-((2,2,6,6-tetramethylpiperidin-4-yl)oxy)pyrazin-2-yl)phenol (100 mg, 0.20 mmol) in CH₂Cl₂ (1 mL) and MeOH (few drops) was added HCl (4 mol/L) in 1,4-dioxane (0.25 mL, 1.0 mmol), and the reaction was stirred at room temperature for 2 h until UPLC showed complete consumption of the starting material. The precipitate was collected by filtration and dried under vacuum to provide 2-[1-(4-piperidyl)pyrazolo[3,4-c]pyridazin-5-yl]-5-(1H-pyrazol-4-yl)phenol; hydrochloride (61 mg, 71% as a yellow solid.

MS m/z 394.5 [M+H]⁺; ¹H NMR (DMSO-d₆) δ: 9.30 (d, J=12.3 Hz, 1H), 9.01 (d, J=1.3 Hz, 1H), 8.45 (d, J=12.3 Hz, 1H), 8.37 (d, J=1.6 Hz, 1H), 8.10 (s, 2H), 7.93 (d, J=8.8 Hz, 1H), 7.19-7.28 (m, 2H), 5.42-5.66 (m, 1H), 2.26 (dd, J=13.1, 3.9 Hz, 2H), 1.81 (dd, J=13.1, 11.0 Hz, 2H), 1.52 (s, 6H), 1.51 (s, 6H); 1H not observed (NH or OH).

Using the procedure described for Example 4, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Cpd Data 10 MS m/z 414.1 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 9.46 (d, J = 10.8 Hz, 1H), 8.65 (s, 1H), 8.59 (d, J = 10.8 Hz, 1H), 8.47 (d, J = 1.2 Hz, 1H), 8.18 (s, 2H), 7.65-7.74 (m, 2H), 5.51-5.56 (m, 1H), 2.23 (dd, J = 12.8, 3.6 Hz, 2H), 1.84 (t, J = 12.8 Hz, 2H), 1.52 (s, 6H, 1.47 (s, 6H).

Example 5 Preparation of Compound 25

Step 1: 6 An oven-dried flask was equipped with a magnetic stir bar and charged with 2,5-dibromopyrazine (500 mg, 2.10 mmol), 4-(3-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazole (970 mg, 2.52 mmol), tetrakis(triphenylphosphine)palladium(0) (121 mg, 0.105 mmol) and K₂CO₃ (870 mg, 6.30 mmol). The flask was sealed with a rubber septum and then evacuated and backfilled with argon. Dioxane (12 mL) and water (3 mL) were added, and the reaction was heated to 90° C. for 5 h. The reaction was cooled to room temperature, diluted with water, and extracted with EtOAc. The combined organic layers were dried over Na₂SO₄ and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with gradient hexanes/EtOAc (30-70% EtOAc) to afford 2-bromo-5-(2-methoxy-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)pyrazine (690 mg, 79%) as an off-white solid. MS m/z 415.1, 417.1 [M+H]⁺.

Step 2: 2-Bromo-5-[2-methoxy-4-(1-tetrahydropyran-2-ylpyrazol-4-yl)phenyl]pyrazine (316 mg, 0.76 mmol) and (1R,5S)-bicyclo[3.2.1]octan-3-ol (80 mg, 0.63 mmol) were mixed in dry DMF (1 mL) and cooled to 0° C. in ice-water bath. Sodium hydride (51 mg, 1.27 mmol, 60% in mineral oil) was added then. The reaction mixture was stirred at room temperature for 16 h, then quenched with water. Precipitate was collected by filtration, dried under vacuum to provide 2-[[(1R,5S)-3-bicyclo[3.2.1]octanyl]oxy]-5-[2-methoxy-4-(1-tetrahydropyran-2-ylpyrazol-4-yl)phenyl]pyrazine (220 mg, 75%) as an off white solid. MS m/z 461.5 [M+H]⁺.

Step 3: To a solution of 2-[[(1R,5S)-3-bicyclo[3.2.1]octanyl]oxy]-5-[2-methoxy-4-(1-tetrahydropyran-2-ylpyrazol-4-yl)phenyl]pyrazine (220 mg, 0.48 mmol) in CH₂Cl₂ was added boron tribromide (1.0 M in CH₂Cl₂, 2.4 mL, 2.4 mmol), and the reaction was stirred at room temperature for 16 h until UPLC showed complete consumption of the starting material. The reaction was quenched with MeOH (10 mL), concentrated under reduced pressure, and purified by silica gel column chromatography eluting with gradient CH₂C2/MeOH (2.5% NH₄OH) (0 to 30% MeOH/NH₄OH). Provided 2-[5-[[(1S,5R)-8-azabicyclo[3.2.1]octan-3-yl]oxy]pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol (122 mg, 70%) as a yellow solid.

MS m/z 364.4 [M+H]⁺; ¹H NMR (DMSO-d₆) δ: 9.00 (d, J=1.6 Hz, 1H), 8.76 (br. s., 1H), 8.69 (br. s., 1H), 8.36 (d, J=1.6 Hz, 1H), 8.09 (s, 2H), 7.92 (d, J=8.2 Hz, 1H), 7.18-7.23 (m, 2H), 5.32-5.45 (m, 1H), 4.08-4.18 (m, 2H), 2.28-2.41 (m, 4H), 1.98-2.08 (m, 2H), 1.87-1.97 (m, 2H); 1H not observed (OH or NH).

Using the procedure described for Example 5, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Cpd Data 7 MS m/z 368.4 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.93 (d, J = 1.5 Hz, 1H), 8.29 (d, J = 1.5 Hz, 1H), 8.12 (br. s., 2H), 7.92 (d, J = 8.2 Hz, 1H), 7.23 (dd, J = 8.2, 1.5 Hz, 1H), 7.21 (s, 1H), 5.42-5.49 (m, 1H), 3.43-3.51 (m, 2H), 3.27-3.32 (m, 2H), 2.26-2.34 (m, 2H), 2.13-2.21 (m, 2H); 3 Hs not observed (2 NHs and OH).

Example 6 Preparation of Compound 8

Step 1: To a mixture of 2-bromo-5-(2-methoxy-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)pyrazine (200 mg, 0.48 mmol) and tert-butyl 4-aminopiperidine-1-carboxylate (96 mg, 0.48 mmol) in EtOH (1 mL) was added a drop of conc. HCl. The reaction was sealed and heated at 120° C. for 16 h until LCMS analysis showed complete consumption of starting material. The mixture was cooled, and the solvent was evaporated providing crude 5-(2-methoxy-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)-N-(piperidin-4-yl)pyrazin-2-amine hydrobromide (248 mg) which was used in the next step without further purification. MS m/z 435.2 [M+H]⁺.

Step 2: To a suspension of 5-(2-methoxy-4-(1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-4-yl)phenyl)-N-(piperidin-4-yl)pyrazin-2-amine hydrobromide (248 mg, 0.48) in CH₂Cl₂ was added boron tribromide (1.0 M in CH₂Cl₂, 2.4 mL, 2.4 mmol), and the reaction was stirred at room temperature for 16 h until UPLC showed complete consumption of the starting material. The reaction was quenched with MeOH (10 mL), concentrated under reduced pressure, and purified by silica gel column chromatography eluting with gradient CH₂C2/MeOH (2.5% NH₄OH) (0 to 30% MeOH/NH₄OH). Provided 2-(5-(piperidin-4-ylamino)pyrazin-2-yl)-5-(1H-pyrazol-4-yl)phenol (128 mg, 79%) as an orange solid.

MS m/z 337.4 [M+H]⁺; ¹H NMR (methanol-d₄) δ: 8.84 (d, J=1.6 Hz, 1H), 8.39 (s, 2H), 8.14-8.22 (m, 1H), 7.88 (d, J=7.9 Hz, 1H), 7.29 (dd, J=8.2, 1.9 Hz, 1H), 7.25 (s, 1H), 4.14-4.27 (m, 1H), 3.53 (dtd, J=13.0, 3.1, 0.9 Hz, 2H), 3.23 (tdd, J=13.0, 3.1, 0.9 Hz, 2H), 2.34 (ddd, J=14.3, 3.1, 0.9 Hz, 2H), 1.79-1.97 (m, 2H); 4Hs not observed (3NHs and OH).

Using the procedure described for Example 6, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Cpd Data 3 MS m/z 487.6 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.82 (s, 1H), 8.03 (s, 1H), 7.97 (s, 2H), 7.81 (d, J = 8.2 Hz, 1H), 7.14(d, J = 8.2 Hz, 1H), 7.11 (s, 1H), 5.00-5.05 (m, 1H), 3.02 (s, 3H), 2.03-2.13 (m, 4H), 1.61-1.67 (m, 6H), 1.48-1.55 (m, 10H), 1.28-1.43 (m, 4H); 3 Hs not observed (2NHs and OH). 6 MS m/z 349.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 9.63 (br s, 2H), 8.89 (s, 1H), 8.11 (s, 2H), 7.96 (s, 1H), 7.86 (d, J = 8.4 Hz, 1H), 7.14-7.17 (m, 2H), 4.16 (d, J = 8.4 Hz, 2H), 4.05 (d, J = 8.4 Hz, 2H), 3.37-3.41 (m, 2H), 3.17-3.22 (m, 2H), 2.19-2.25 (m, 2H); 1H is not observed (NH or OH). 20 MS m/z 351.4 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.80 (d, J = 1.5 Hz, 1H), 8.08 (d, J = 1.5 Hz, 1H), 7.98 (br s, 2H), 7.81 (d, J = 8.2 Hz, 1H), 7.16 (dd, J = 8.2, 1.8 Hz, 1H), 7.13 (d, J = 1.5 Hz, 1H), 4.68 (tt, J = 12.5, 4.3 Hz, 1H), 3.26 (d, J = 12.5 Hz, 2H), 3.05 (s, 3H), 2.86 (td, J = 12.5, 3.0 Hz, 2H), 1.88 (ddd, J = 25.3, 12.5, 4.3 Hz, 2H), 1.80 (d, J = 12.5 Hz, 2H); 3Hs not observed (2NHs and OH). 21 MS m/z 349.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 9.63 (br.s., 2H), 8.89 (s, 1H), 8.11 (s, 2H), 7.96 (s, 1H), 7.86 (d, J = 8.4 Hz, 1H), 7.14-7.17 (m, 2H), 4.16 (d, J = 8.4 Hz, 2H), 4.05 (d, J = 8.4 Hz, 2H), 3.37-3.41 (m, 2H), 3.17-3.22 (m, 2H), 2.19-2.25 (m, 2H); 1H is not observed (NH or OH).

Example 7 Preparation of Compound 48

Step 1: A solution of 2,5-dibromopyrazine (9.0 g, 37.8 mmol), 2,2,6,6-tetramethylpiperidin-4-amine (11.8 g, 75.5 mmol) and DIPEA (9.8 g, 76 mmol) in n-BuOH (100 mL) was stirred at 130° C. for 24 h. After cooling to room temperature, the solvent was removed, and the residue was purified using silica gel chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 15% MeOH) to give 5-bromo-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (10 g, 84% yield) as an off-white solid. MS: m/z: 313.1, 315.1 [M+H]⁺.

Step 2: To round bottom flask were added: 5-bromo-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (10.0 g, 31.9 mmol), 3-(methoxymethoxy)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl 4-methylbenzenesulfonate (13.9 g, 32.0 mmol), K₂CO₃ (8.8 g, 64 mmol) and PdCl₂dppf (234 mg, 0.32 mmol). The mixture was degassed with nitrogen and 1,4-dioxane (100 mL) and water (10 mL) were then added. The mixture was stirred at 100° C. for 16 h. After cooling to room temperature, the solvent was removed, and the residue was purified using silica gel chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 30% MeOH) to give 3-(methoxymethoxy)-4-(5-((2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl 4-methylbenzenesulfonate (4.5 g, 26% yield) as a brown solid. MS: m/z: 541.3 [M+H]⁺.

Step 3: To a solution of 3-(methoxymethoxy)-4-(5-((2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl 4-methylbenzenesulfonate (2.5 g, 4.6 mmol) in EtOH (10 mL) and water (1 mL) was added KOH (520 mg, 9.27 mmol). The mixture was stirred at 80° C. for 2 h. The solvent was removed, and the residue was flushed through a silica plug using 0-10% MeOH in CH₂Cl₂ to yield crude 3-(methoxymethoxy)-4-(5-((2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenol (2.0 g) as a brown solid, which was used in the next step without further purification. MS: m/z: 387.3 [M+H]⁺.

Step 4: To a solution of 3-(methoxymethoxy)-4-(5-((2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenol (2.43 g, 6.29 mmol) in CH₂Cl₂ (40 mL) was added PhNTf₂ (6.8 g, 19 mmol) and Et₃N (1.9 g, 19 mmol). The reaction mixture was stirred at room temperature for 16. The solvent was removed and the residue was purified using silica gel chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 30% MeOH) to give 3-(methoxymethoxy)-4-(5-((2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl trifluoromethanesulfonate (1.9 g, 58% yield) as a pale yellow solid. MS: m/z: 519.2 [M+H]⁺.

Step 5: A mixture of 3-(methoxymethoxy)-4-(5-((2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl trifluoromethanesulfonate (1.5 g, 2.9 mmol), bis(pinacolato)diboron (773 mg, 3.05 mmol), Pd(dppf)Cl₂ (220 mg, 0.30 mmol) and KOAc (568 mg, 5.8 mmol) was degassed with nitrogen. 1,4-Dioxane (25 mL) was added and the reaction mixture was stirred at 100° C. for 16 h. The solvent was removed to give the crude product, which was purified by silica gel chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 30% MeOH) to yield 5-(2-(methoxymethoxy)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (840 mg, 59% yield) as a brown-black solid. MS: m/z: 497.3 [M+H]⁺.

Step 6: A mixture of 5-(2-(methoxymethoxy)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (180 mg, 0.36 mmol), 2-bromopyridine (56 mg, 0.35 mmol), K₂CO₃ (100 mg, 0.73 mmol) and SPhos Pd G2 (26 mg, 0.036 mmol) was degassed with nitrogen. 1,4-Dioxane (5 mL) and water (0.5 mL) were added, and the reaction mixture was stirred at 70° C. for 16 h. The solvent was removed, and the residue was purified by silica gel chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 30% MeOH) to give 5-(2-(methoxymethoxy)-4-(pyridin-2-yl)phenyl)-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (90 mg, 55% yield) as a brown solid. MS: m/z: 448.3 [M+H]⁺.

Step 7: To a solution of 5-(2-(methoxymethoxy)-4-(pyridin-2-yl)phenyl)-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (90 mg, 0.20 mmol) in CH₂Cl₂ (2 mL) was added 4N HCl in dioxane (2 mL) and the reaction mixture was stirred at room temperature for 2 h. The mixture was poured into ice water, neutralized with saturated aqueous NaHCO₃and extracted with CH₂Cl₂ (150 mL×3). The combined organic phases were concentrated, and the residue was purified by Prep-HPLC to give 5-(pyridin-2-yl)-2-(5-((2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenol (34 mg, 42% yield) as a pale yellow solid.

MS: m/z: 404.2[M+H]⁺; ¹H NMR (DMSO-d₆) δ: 8.89 (s, 1H), 8.66 (d, J=4.4 Hz, 1H), 8.42 (s, 1H), 7.94-7.98 (m, 3H), 7.84-7.89 (m, 1H), 7.66 (d, J=1.6 Hz, 1H), 7.60 (dd, J=8.4, 1.6 Hz, 1H), 7.40 (d, J=7.6 Hz, 1H), 7.33-7.36 (m, 1H), 4.28-4.30 (m, 1H), 1.94-1.98 (m, 2H), 1.28-1.38 (m, 14H); 1H not observed (OH or NH).

Using the procedure described for Example 7, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Cpd Data 43 MS m/z 425.5 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.86 (s, 1H), 8.09 (s, 1H), 7.94 (s, 1H), 7.78 (d, J = 9.8 Hz, 1H), 7.08-7.20 (m, 2H), 5.21-5.35 (m, 1H), 3.04 (s, 3H), 1.72- 1.88 (m, 4H), 1.53 (s, 6H), 1.40 (s, 6H); 3Hs not observed (2 NHs and OH) 47 MS m/z 405.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.88-8.90 (m, 3H), 8.40 (s, 1H), 7.98- 8.02 (m, 2H), 7.89-7.94 (m, 2H), 7.43 (t, J = 4.8 Hz, 1H), 7.37 (d, J = 7.6 Hz, 1H), 4.27-4.30 (m, 1H), 1.92-1.96 (m, 2H), 1.22-1.33 (m, 14H); 1H not observed (OH or NH) 49 MS m/z 435.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.90 (s, 1H), 8.84 (s, 1H), 8.40 (br s, 1H), 7.98-8.00 (m, 2H), 7.73 (d, J = 1.6 Hz, 1H), 7.68 (dd, J = 8.4, 1.6 Hz, 1H), 7.45 (s, 2H), 4.27-4.30 (m, 1H), 3.98 (s, 3H), 1.94-1.98 (m, 2H), 1.26-1.37 (m, 14H); 1H not observed (OH or NH) 53 MS m/z 444.8 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 9.24 (d, J = 1.2 Hz, 1H), 9.16 (s, 1H), 8.90 (s, 1H), 8.40 (br s, 1H), 8.13 (s, 1H), 7.97-8.00 (m, 2H), 7.85 (d, J = 0.8 Hz, 1H), 7.62 (d, J = 1.6 Hz, 1H), 7.55 (dd, J = 8.0, 1.6 Hz, 1H), 7.39 (d, J = 7.2 Hz, 1H), 4.25-4.32 (m, 1H),1.94-1.99 (m, 2H), 1.27-1.38 (m, 14H); 1H not observed (OH or NH) 55 MS m/z 407.1 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 11.95 (br s, 1H), 8.81 (s, 1H), 7.91 (s, 1H), 7.86 (d, J = 8.4 Hz, 1H), 7.72 (d, J = 2.0 Hz, 1H), 7.27-7.30 (m, 2H), 7.16 (d, J = 7.6 Hz, 1H), 6.68 (d, J = 2.4 Hz, 1H), 4.20-4.25 (m, 1H), 3.88 (s, 3H), 1.81-1.86 (m, 2H), 1.23 (s, 6H), 1.00-1.06 (m, 8H); 1H not observed (OH or NH) 56 MS m/z 444.1 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.92 (s, 1H), 8.43 (br s, 1H), 8.35 (s, 1H), 8.20 (d, J = 9.6 Hz, 1H), 8.00-8.06 (m, 2H), 7.79-7.82 (m, 2H), 7.64 (d, J = 1.6 Hz, 1H), 7.58 (dd, J = 8.4,1.6 Hz, 1H), 7.47 (d, J = 7.6 Hz, 1H), 4.30-4.32 (m, 1H), 1.96-2.00 (m, 2H), 1.30-1.40 (m, 14H); 1H not observed (OH or NH) 57 MS m/z 411.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.83 (s, 1H), 8.40 (br s, 1H), 8.18 (d, J = 2.0 Hz, 1H), 7.95 (s, 1H), 7.87 (d, J = 8.0 Hz, 1H), 7.34 (d, J = 7.6 Hz, 1H), 7.08- 7.10 (m, 2H), 4.26-4.30 (m, 1H), 1.94-1.98 (m, 2H), 1.27-1.37 (m, 14H); 2Hs not observed (OH and NH) 58 MS m/z 393.1 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.84 (s, 1H), 8.38 (br s, 1H), 7.94 (s, 1H), 7.89 (d, J = 8.4 Hz, 1H), 7.70 (br s, 1H), 7.29-7.33 (m, 3H), 6.70 (d, J = 2.4 Hz, 1H), 4.26-4.28 (m, 1H), 1.91-1.96 (m, 2H), 1.22-1.34 (m, 14H); 2Hs not observed (OH and NH) 65 MS m/z 397.4 [M + H]⁺; ¹H NMR (methanol-d₄) δ: 8.74-8.78 (m, 1H), 7.88-7.92 (m, 2H), 7.77 (d, J = 7.3 Hz, 1H), 7.10-7.16 (m, 2H), 3.88-3.93 (m, 1H), 3.66-3.77 (m, 2H), 3.51 (br d, J = 7.3 Hz, 1H), 3.19-3.24 (m, 1H), 2.33-2.41 (m, 1H), 1.89-1.98 (m, 1H), 1.23 (s, 9H); 3Hs not observed (2 NHs and OH)

Example 8 Preparation of Compound 61

Step 1: A mixture of 5-bromo-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (0.8 g, 2.44 mmol), 2-(4-chloro-2-(methoxymethoxy)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.87 g, 2.91 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (0.17 g, 0.23 mmol) and aq. 2N K₂CO₃ (5 mL, 4.89 mmol) was purged with argon for 15 min. Dioxane (12 ml) was added and the reaction mixture was then heated to 100° C. for 4 h. The reaction mixture was cooled to room temperature, the solvent was evaporated under reduced pressure, and the residue was partitioned between EtOAc and aqueous saturated NaHCO₃. The organic layers were dried over Na₂SO₄, and the solvent was evaporated. The residue was purified using silica gel chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 30% MeOH) to afford 5-(4-chloro-2-(methoxymethoxy)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (0.62 g, 60%). MS m/z 419.5 [M+H]+

Step 2: Tris(dibenzylideneacetone)dipalladium(0) (2.6 mg, 0.0028 mmol) and 2-di-tert-butylphosphino-3,4,5,6-tetramethyl-2′,4′,6′-triisopropyl-1,1′-biphenyl (3.5 mg, 0.0070 mmol) were suspended in 5:1 toluene/dioxane (1 mL). The purple solution was sparged with argon for 5 minutes, then heated to 120° C. for 5 minutes. The solution was cooled to room temperature and tripotassium phosphate (30 mg, 0.137 mmol), 1,2,3-triazole (5 L, 0.086 mmol), and 5-(4-chloro-2-(methoxymethoxy)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (42 mg, 0.1 mmol). The suspension was sparged once more with argon, then heated to 120° C. for 1 h until complete consumption of aryl chloride, as monitored by UPLC. The reaction was cooled to room temperature and the product was purified using silica gel chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 30% MeOH) to yield 5-(2-(methoxymethoxy)-4-(2H-1,2,3-triazol-2-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (40 mg, 88% yield).

MS m/z 452.4 [M+H]⁺; ¹H NMR (methanol-d₄) δ: 8.70 (d, J=1.2 Hz, 1H), 8.15 (d, J=1.2 Hz, 1H), 8.03 (d, J=2.7 Hz, 1H), 7.95-7.96 (m, 2H), 7.82 (s, 2H), 5.38 (s, 2H), 5.15-5.21 (m, 1H), 3.51 (s, 3H), 3.03 (s, 3H), 1.68-1.72 (m, 2H), 1.57-1.62 (m, 2H), 1.41 (s, 6H), 1.27 (s, 6H); 1NH not observed.

Step 3: To a solution of 5-(2-(methoxymethoxy)-4-(2H-1,2,3-triazol-2-yl)phenyl)-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine (25 mg, 0.044 mmol) in MeOH (1 ml) was added 4N HCl in dioxane (1 mL). The reaction mixture was stirred at room temperature for 2 h. The solvents were evaporated and the residue was purified using silica gel chromatography eluting with a MeOH/CH₂Cl₂ gradient (0 to 30% MeOH) to yield 2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)-5-(2H-1,2,3-triazol-2-yl)phenol (20 mg, 76% yield).

MS m/z 408.5 [M+H]⁺; ¹H NMR (methanol-d₄) δ: 8.90 (s, 1H), 8.10 (s, 1H), 7.99 (d, J=8.5 Hz, 1H), 7.94 (s, 2H), 7.60-7.66 (m, 2H), 5.20-5.31 (m, 1H), 3.05 (s, 3H), 1.67-1.81 (m, 4H), 1.48 (s, 6H), 1.33-1.37 (m, 6H); 2Hs not observed (NH and OH).

Using the procedure described for Example 8, additional compounds described herein may be prepared by substituting the appropriate starting material, suitable reagents and reaction conditions, obtaining compounds such as those selected from:

Cpd Data 50 MS m/z 393.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.88 (s, 1H), 8.40 (br s, 1H), 8.30 (s, 1H), 7.97-8.00 (m, 2H), 7.78 (s, 1H), 7.45 (d, J = 7.2 Hz, 1H), 7.16-7.22 (m, 2H), 7.10 (s, 1H), 4.27-4.30 (m, 1H), 1.97-2.00 (m, 2H), 1.31-1.40 (m, 14H); 1H not observed (OH or NH) 51 MS m/z 394.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.84 (d, J = 1.2 Hz, 1H), 8.42 (br s, 1H), 8.12 (s, 2H), 8.02 (d, J = 8.8 Hz, 1H), 7.97 (d, J = 1.2 Hz, 1H), 7.52-7.57 (m, 2H), 7.32 (d, J = 7.6 Hz, 1H), 4.26-4.29 (m, 1H), 1.90-1.95 (m, 2H), 1.20-1.32 (m, 14H); 1H not observed (OH or NH) 59 MS m/z 411.2 [M + H]⁺; ¹H NMR (DMSO-d₆) δ: 8.85 (s, 1H), 8.71 (d, J = 4.4 Hz, 1H), 8.42 (br s, 1H), 7.96-7.98 (m, 2H), 7.84 (d, J = 4.0 Hz, 1H), 7.36-7.41 (m, 2H), 7.30 (dd, J = 8.4, 2.0 Hz, 1H), 4.26-4.31 (m, 1H), 1.95-1.99 (m, 2H), 1.28-1.38 (m, 14H); 1H not observed (OH or NH)

Biological Examples

The following in vitro biological examples demonstrate the usefulness of the compounds of the present description for treating Huntington's disease.

To describe in more detail and assist in understanding the present description, the following non-limiting biological examples are offered to more fully illustrate the scope of the description and are not to be construed as specifically limiting the scope thereof. Such variations of the present description that may be now known or later developed, which would be within the purview of one skilled in the art to ascertain, are considered to fall within the scope of the present description and as hereinafter claimed.

Compounds of Formula (I) were tested using the Meso Scale Discovery (MSD) Assay provided in International Application No. PCT/US2016/066042, filed on Dec. 11, 2016 and claiming priority to United States Provisional Application U.S. 62/265,652 filed on Dec. 10, 2015, the entire contents of which are incorporated herein by reference.

The Endogenous Huntingtin Protein assay used in Example 1 was developed using the ELISA-based MSD electrochemiluminescence assay platform.

Example 1 Endogenous Huntingtin Protein Assay

Meso Scale Discovery (MSD) 96-well or 384-well plates were coated overnight at 4° C. with MW1 (expanded polyglutamine) or MAB2166 monoclonal antibody (for capture) at a concentration of 1 μg/mL in PBS (30 μL per well). Plates were then washed three times with 300 μL wash buffer (0.05% Tween-20 in PBS) and blocked (100 μL blocking buffer; 5% BSA in PBS) for 4-5 hours at room temperature with rotational shaking and then washed three times with wash buffer.

Samples (25 μL) were transferred to the antibody-coated MSD plate and incubated overnight at 4° C. After removal of the lysates, the plate was washed three times with wash buffer, and 25 μL of #5656S (Cell signaling; rabbit monoclonal) secondary antibody (diluted to 0.25 μg/mL in 0.05% Tween-20 in blocking buffer) was added to each well and incubated with shaking for 1 Hour at room temperature. Following incubation with the secondary antibody, the wells were rinsed with wash buffer after which 25 μL of goat anti-rabbit SULFO TAG secondary detection antibody (required aspect of the MSD system) (diluted to 0.25 μg/mL in 0.05% Tween-20 in blocking buffer) was added to each well and incubated with shaking for 1 hour at room temperature. After rinsing three times with wash buffer, 150 μL of read buffer T with surfactant (MSD) were added to each empty well, and the plate was imaged on a SI 6000 imager (MSD) according to manufacturers' instructions provided for 96- or 384-well plates. The resulting IC₅₀ values (μM) for compounds tested are shown in Table 1.

As shown in Table 1, test compounds described herein had the following IC₅₀ values, an IC₅₀ value between >3 μM and <9 μM is indicated by a single star (*), an IC₅₀ value between >1 μM and <3 μM is indicated by two stars (**), an IC₅₀ value between >0.5 μM and <1 μM is indicated by three stars (***), an IC₅₀ value between >0.1 μM and <0.5 μM is indicated by four stars (****) and an IC₅₀ value of <0.1 μM is indicated by five stars (*****).

TABLE 1 Cpd IC₅₀ 1 ***** 2 *** 3 ** 4 ** 5 *** 6 ** 7 ** 8 ** 9 ** 10 ** 11 **** 12 *** 13 ***** 14 ** 15 ***** 16 *** 17 **** 18 ** 19 ** 20 *** 21 ** 22 ***** 23 **** 24 ***** 25 * 26 ***** 27 **** 28 *** 41 *** 42 **** 43 **** 44 **** 45 *** 46 ***** 47 ** 48 * 49 ***** 50 **** 51 *** 52 ***** 53 **** 54 ***** 55 *** 56 ***** 57 ***** 58 **** 59 ** 60 ***** 61 **** 62 ***** 63 **** 64 ***** 65 *****

Without regard to whether a document cited herein was specifically and individually indicated as being incorporated by reference, all documents referred to herein are incorporated by reference into the present application for any and all purposes to the same extent as if each individual reference was fully set forth herein.

Having now fully described the subject matter of the claims, it will be understood by those having ordinary skill in the art that the same can be performed within a wide range of equivalents without affecting the scope of the subject matter or particular aspects described herein. It is intended that the appended claims be interpreted to include all such equivalents. 

1. A compound comprising, a compound of Formula (I):

or a form thereof, wherein: X is CHR_(1a), C═O, O, NR_(1b), or a bond; R_(1a) is independently selected from hydrogen, halogen, hydroxyl, cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, and hydroxyl-C₁₋₄alkyl; R_(1b) is independently selected from hydrogen, C₁₋₄alkyl, deutero-C₁₋₄alkyl, and halo-C₁₋₄alkyl; B is heterocyclyl, wherein heterocyclyl is a saturated or partially unsaturated 3-7 membered monocyclic, 6-10 membered bicyclic or 13-16 membered polycyclic ring system having 1, 2, or 3 heteroatom ring members independently selected from N, O, or S, each optionally substituted with 1, 2, 3, 4, or 5 substituents each selected from R₂; R₂ is independently selected from halogen, C₁₋₄alkyl, deutero-C₁₋₄alkyl, amino, C₁₋₄alkyl-amino, and (C₁₋₄alkyl)₂-amino; R₃ is independently selected from halogen, hydroxyl, cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, C₁₋₄alkyl-amino, (C₁₋₄alkyl)₂-amino, C₁₋₄alkoxy, halo-C₁₋₄alkoxy, heteroaryl, heterocyclyl, and phenyl, wherein heteroaryl is a 3-7 membered monocyclic or 6-10 membered bicyclic ring system having 1, 2, 3, or 4 heteroatom ring members independently selected from N, O, or S, wherein heterocyclyl is a saturated or partially unsaturated 3-7 membered monocyclic, 6-10 membered bicyclic or 13-16 membered polycyclic ring system having 1, 2, or 3 heteroatom ring members independently selected from N, O, or S, and wherein each instance of phenyl, heteroaryl or heterocyclyl is optionally substituted with 1 or 2 substituents each selected from R₄; n is n is 1, 2 or 3; and R₄ is independently selected from halogen, hydroxyl, cyano, C₁₋₄alkyl, deutero-C₁₋₄alkyl, halo-C₁₋₄alkyl, amino, C₁₋₄alkyl-amino, (C₁₋₄alkyl)₂-amino, C₁₋₄alkoxy, and halo-C₁₋₄alkoxy; wherein a form of the compound is selected from the group consisting of a salt, hydrate, solvate, racemate, enantiomer, diastereomer, stereoisomer, and tautomer form thereof.
 2. The compound of claim 1, wherein X is selected from NR_(1b) and a bond.
 3. The compound of claim 1, wherein B is selected from azetidinyl, tetrahydrofuranyl, pyrrolidinyl, piperidinyl, piperazinyl, 1,4-diazepanyl, 1,2-dihydropyridinyl, 1,2,5,6-tetrahydropyridinyl, 1,2,3,6-tetrahydropyridinyl, hexahydrocyclopentapyrrol-(1H)-yl, hexahydropyrrolo[3,2-b]pyrrol-(2H)-yl, hexahydropyrrolo[3,4-b]pyrrol-(2H)-yl, (3aS,6aS)-hexahydropyrrolo[3,4-b]pyrrol-(2H)-yl, hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, (3aS,6aS)-hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, (3aR,6aR)-hexahydropyrrolo[3,4-b]pyrrol-(1H)-yl, hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, (3aR,6aS)-hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, octahydro-2H-pyrrolo[3,4-c]pyridinyl, octahydro-5H-pyrrolo[3,2-c]pyridinyl, octahydro-6H-pyrrolo[3,4-b]pyridinyl, (4aR,7aR)-octahydro-6H-pyrrolo[3,4-b]pyridinyl, (4aS,7aS)-octahydro-6H-pyrrolo[3,4-b]pyridinyl, hexahydropyrrolo[1,2-a]pyrazin-(2H)-one, hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (7R,8aS)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aS)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aR)-hexahydropyrrolo[1,2-a]pyrazin-(1H)-yl, hexahydro-1H-cyclobuta[1.2-c:1,4-c′]dipyrrol-(3H)-yl, (8aS)-octahydropyrrolo[1,2-a]pyrazin-(1H)-yl, (8aR)-octahydropyrrolo[1,2-a]pyrazin-(1H)-yl, octahydro-2H-pyrido[1,2-a]pyrazinyl, hexahydropyrrolo[3,4-b][1,4]oxazin-(2H)-yl, 5-azaspiro[2.4]heptanyl, 2-oxa-6-azaspiro[3.4]octanyl, 3-azabicyclo[3.1.0]hexanyl, 8-azabicyclo[3.2.1]octanyl, (1R,5S)-8-azabicyclo[3.2.1]octanyl, 8-azabicyclo[3.2.1]oct-2-en-yl, (1R,5S)-8-azabicyclo[3.2.1]oct-2-en-yl, 9-azabicyclo[3.3.1]nonanyl, (1R,5S)-9-azabicyclo[3.3.1]nonanyl, 2,5-diazabicyclo[2.2.1]heptanyl, (1S,4S)-2,5-diazabicyclo[2.2.1]heptanyl, 1,4-diazabicyclo[3.1.1]heptanyl, 3,6-diazabicyclo[3.2.0]heptanyl, 2,5-diazabicyclo[2.2.2]octanyl, 1,4-diazabicyclo[3.2.1]octanyl, 3,8-diazabicyclo[3.2.1]octanyl, (1R,5S)-3,8-diazabicyclo[3.2.1]octanyl, 1,4-diazabicyclo[3.2.2]nonanyl, azaspiro[3.3]heptanyl, 4,7-diazaspiro[2.5]octanyl, 2,6-diazaspiro[3.3]heptan-2-yl, 2,6-diazaspiro[3.4]octanyl, 1,7,-diazaspiro[4.4]nonanyl, 1,7-diazaspiro[3.5]nonanyl, 2,6-diazaspiro[3.5]nonanyl, 2,7-diazaspiro[3.5]nonanyl, 5,8-diazaspiro[3.5]nonanyl, 2,7-diazaspiro[4.4]nonanyl, 2,7-diazaspiro[4.5]decanyl, 2,8-diazaspiro[4.5]decanyl, 6,9-diazaspiro[4.5]decyl, and 7-azadispiro[5.1.5⁸.3⁶]hexadecanyl, optionally substituted with 1, 2, 3, 4, or 5 R₂ substituents.
 4. The compound of claim 1, wherein B is selected from pyrrolidinyl, piperidinyl, hexahydropyrrolo[3,4-c]pyrrol-(1H)-yl, 8-azabicyclo[3.2.1]octanyl, 2,6-diazaspiro[3.4]octanyl, and 7-azadispiro[5.1.5⁸.3⁶]hexadecanyl, optionally substituted with 1, 2, 3, 4, or 5 R₂ substituents.
 5. The compound of claim 1, wherein R₃ is heteroaryl selected from thienyl, 1H-pyrazolyl, 1H-imidazolyl, 1,3-thiazolyl, oxazolyl, 1,2,4-oxadiazolyl, 1,2,4-thiadiazolyl, 1H-1,2,3-triazolyl, 2H-1,2,3-triazolyl, 1H-1,2,4-triazolyl, 1H-tetrazolyl, 2H-tetrazolyl, pyridinyl, pyridin-2(1H)-on-yl, pyrimidinyl, pyrimidin-4(3H)-on-yl, pyridazinyl, pyridazin-3(2H)-on-yl, 1,2,4-triazinyl, 1,3,5-triazinyl, 1H-indolyl, 1H-indazolyl, 2H-indazolyl, indolizinyl, benzofuranyl, benzothienyl, 1H-benzimidazolyl, 1,3-benzoxazolyl, 1,3-benzothiazolyl, 1,3-benzodioxolyl, 1,2,3-benzotriazolyl, 9H-purinyl, furo[3,2-b]pyridinyl, furo[3,2-c]pyridinyl, furo[2,3-c]pyridinyl, 1,3-oxazolo[5,4-b]pyridinyl, thieno[3,2-c]pyridinyl, thieno[2,3-d]pyrimidinyl, 1H-pyrrolo[2,3-b]pyridinyl, 1H-pyrrolo[2,3-c]pyridinyl, pyrrolo[1,2-a]pyrimidinyl, pyrrolo[1,2-a]pyrazinyl, pyrrolo[1,2-b]pyridazinyl, pyrazolo[1,5-a]pyridin-yl, pyrazolo[1,5-a]pyridinyl, 1H-pyrazolo[3,4-b]pyrazinyl, 1H-pyrazolo[3,4-b]pyridinyl, 1H-pyrazolo[3,4-b]pyridinyl, 1H-pyrazolo[3,4-c]pyridinyl, 1H-pyrazolo[3,4-c]pyridinyl, 1H-pyrazolo[4,3-b]pyridinyl, 1H-pyrazolo[4,3-b]pyridinyl, 1H-pyrazolo[4,3-d]pyrimidinyl, 2H-pyrazolo[4,3-b]pyridinyl, 2H-pyrazolo[4,3-c]pyridin-yl, 5H-pyrrolo[2,3-b]pyrazinyl, pyrazolo[1,5-a]pyrazinyl, imidazo[1,2-a]pyridinyl, imidazo[1,2-a]pyridinyl, imidazo[1,2-a]pyrimidinyl, imidazo[1,2-a]pyrimidinyl, imidazo[1,2-c]pyrimidinyl, imidazo[1,2-b]pyridazinyl, imidazo[1,2-b]pyridazinyl, imidazo[1,2-a]pyrazinyl, imidazo[1,2-a]pyrazinyl, 1H-imidazo[4,5-b]pyridinyl, 3H-imidazo[4,5-b]pyridinyl, imidazo[2,1-b][1,3]thiazolyl, imidazo[2,1-b][1,3,4]thiadiazolyl, [1,3]oxazolo[4,5-b]pyridinyl, [1,2,3]triazolo[1,5-a]pyridinyl, [1,2,3]triazolo[1,5-a]pyridinyl, 1H-[1,2,3]triazolo[4,5-b]pyridinyl, 3H-[1,2,3]triazolo[4,5-b]pyridinyl, tetrazolo[1,5-a]pyridinyl, tetrazolo[1,5-b]pyridazinyl, quinolinyl, isoquinolinyl, and quinoxalinyl, optionally substituted with 1 or 2 R₄ substituents.
 6. The compound of claim 1, wherein R₃ is heteroaryl selected from 1H-pyrazolyl, 1H-imidazolyl, 2H-1,2,3-triazolyl, 1H-1,2,4-triazolyl, pyridinyl, pyridin-2(1H)-on-yl, pyrimidinyl, 1,3,5-triazinyl, imidazo[1,2-b]pyridazinyl, and imidazo[1,2-a]pyrazinyl, optionally substituted with 1 or 2 R₄ substituents.
 7. The compound of claim 1, wherein the form of the compound is a compound salt selected from hydrochloride, hydrobromide, trifluoroacetate, formate, dihydrochloride, trihydrochloride, tetrahydrochloride, dihydrobromide and ditrifluoroacetate.
 8. A compound selected from the group consisting of: 4-(3-hydroxy-4-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenyl)pyridin-2-ol; 5-(1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)oxy]pyrazin-2-yl}phenol; 2-{5-[(7-azadispiro[5.1.58.36]hexadecan-15-yl)(methyl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol; 5-[2,5-dichloro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 5-(1H-imidazol-1-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 2-[5-(hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl)pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol; 2-{5-[(piperidin-4-yl)oxy]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol; 2-{5-[(piperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol; 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-[5-(trifluoromethyl)-1H-pyrazol-4-yl]phenol; 2-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]-5-[(2,2,6,6-tetramethylpiperidin-4-yl)oxy]pyrazine; 5-[2-fluoro-5-methyl-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 5-(5-methyl-1H-pyrazol-4-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 5-(3-amino-1H-pyrazol-1-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-[2,5-difluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 5-[3-fluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 5-[3,5-difluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 4-(3-hydroxy-4-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenyl)-1-methylpyridin-2(1H)-one; 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-1-yl)phenol; 2-{5-[methyl(piperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol; 2-[5-(2,6-diazaspiro[3.4]octan-2-yl)pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol; 4-fluoro-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol; 5-[5-chloro-2-fluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 4-fluoro-5-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-2-(1H-pyrazol-4-yl)benzonitrile; 2-[5-(8-azabicyclo[3.2.1]oct-3-yloxy)pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol; 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol; 5-(1-methyl-H-pyrazol-4-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-[1-(2H3)methyl-1H-pyrazol-4-yl]-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; (5-(2-hydroxy-4-(1H-pyrazol-4-yl)phenyl)pyrazin-2-yl)(2,2,6,6-tetramethylpiperidin-4-yl)methanone; 2-(5-(2-hydroxy-4-(1H-pyrazol-4-yl)phenyl)pyrazin-2-yl)-2-(2,2,6,6-tetramethylpiperidin-4-yl)acetonitrile; 2-(5-(amino(2,2,6,6-tetramethylpiperidin-4-yl)methyl)pyrazin-2-yl)-5-(1H-pyrazol-4-yl)phenol; 2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)-5-(1,3,5-triazin-2-yl)phenol; 4-(3-hydroxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl)-1,3,5-triazin-2-ol; 5-(4-amino-1,3,5-triazin-2-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenol; 5-(4-chloro-1,3,5-triazin-2-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenol; 5-(5-chloro-1H-pyrazol-4-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenol; 4-(3-hydroxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl)-1H-pyrazole-5-carbonitrile; 5-(1,5-dimethyl-1H-pyrazol-4-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenol; 5-(5-chloro-1-methyl-1H-pyrazol-4-yl)-2-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenol; 4-(3-hydroxy-4-(5-(methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino)pyrazin-2-yl)phenyl)-1-methyl-1H-pyrazole-5-carbonitrile; 5-[2,3-difluoro-4-(4-methyl-1H-imidazol-1-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 5-[2,5-difluoro-4-(3-methyl-1H-1,2,4-triazol-1-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine; 5-(3-fluoro-1H-pyrazol-4-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(pyridin-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(pyridin-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(pyrimidin-2-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(pyridin-2-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(6-methoxypyrimidin-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(1H-imidazol-1-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(2H-1,2,3-triazol-2-yl)phenol; 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol; 5-(imidazo[1,2-a]pyrazin-6-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(1-methyl-1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(1-methyl-1H-pyrazol-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(imidazo[1,2-b]pyridazin-6-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(5-fluoro-1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(1H-pyrazol-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 5-(4-fluoro-1H-pyrazol-1-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol; 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-[1-(2H3)methyl-1H-pyrazol-4-yl]phenol; 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(2H-1,2,3-triazol-2-yl)phenol; 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(1-methyl-1H-pyrazol-4-yl)phenol; N-tert-butyl-1-{5-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]pyrazin-2-yl}pyrrolidin-3-amine; N-tert-butyl-1-{5-[2,5-difluoro-4-(1H-pyrazol-4-yl)phenyl]pyrazin-2-yl}pyrrolidin-3-amine; and 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(3-fluoro-1H-pyrazol-4-yl)phenol, wherein a form of the compound is selected from the group consisting of a salt, hydrate, solvate, racemate, enantiomer, diastereomer, stereoisomer, and tautomer form thereof.
 9. The compound of claim 6, wherein the form of the compound is a compound salt or a form thereof selected from the group consisting of: 5-(1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)oxy]pyrazin-2-yl}phenol hydrochloride; 2-[5-(hexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl)pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol tetrahydrochloride; 2-{5-[(piperidin-4-yl)oxy]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol trihydrochloride; 2-{5-[(piperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol tetrahydrochloride; 2-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]-5-[(2,2,6,6-tetramethylpiperidin-4-yl)oxy]pyrazine trihydrochloride; 5-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]-N-methyl-N-(2,2,6,6-tetramethylpiperidin-4-yl)pyrazin-2-amine hydrochloride; 2-[5-(8-azabicyclo[3.2.1]oct-3-yloxy)pyrazin-2-yl]-5-(1H-pyrazol-4-yl)phenol hydrochloride; 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol hydrobromide; 5-[1-(2H3)methyl-1H-pyrazol-4-yl]-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol dihydrochloride; 5-(3-fluoro-1H-pyrazol-4-yl)-2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol dihydrochloride; 5-(pyridin-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(pyridin-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(pyrimidin-2-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(pyridin-2-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(6-methoxypyrimidin-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(1H-imidazol-1-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(2H-1,2,3-triazol-2-yl)phenol formate; 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(1H-pyrazol-4-yl)phenol dihydrochloride; 5-(imidazo[1,2-a]pyrazin-6-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(1-methyl-1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(imidazo[1,2-b]pyridazin-6-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(5-fluoro-1H-pyrazol-4-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(1H-pyrazol-3-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 5-(4-fluoro-1H-pyrazol-1-yl)-2-{5-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}phenol formate; 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-[1-(2H3)methyl-1H-pyrazol-4-yl]phenol dihydrochloride; 2-{5-[methyl(2,2,6,6-tetramethylpiperidin-4-yl)amino]pyrazin-2-yl}-5-(2H-1,2,3-triazol-2-yl)phenol dihydrochloride; 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(1-methyl-1H-pyrazol-4-yl)phenol dihydrochloride; N-tert-butyl-1-{5-[2,3-difluoro-4-(1H-pyrazol-4-yl)phenyl]pyrazin-2-yl}pyrrolidin-3-amine dihydrochloride; N-tert-butyl-1-{5-[2,5-difluoro-4-(1H-pyrazol-4-yl)phenyl]pyrazin-2-yl}pyrrolidin-3-amine dihydrochloride; and 2-{5-[3-(tert-butylamino)pyrrolidin-1-yl]pyrazin-2-yl}-5-(3-fluoro-1H-pyrazol-4-yl)phenol dihydrochloride, wherein a form of the compound is selected from the group consisting of a salt, hydrate, solvate, racemate, enantiomer, diastereomer, stereoisomer, and tautomer form thereof.
 10. A method for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of claim
 1. 11. The method of claim 10, wherein the effective amount of the compound is in a range of from about 0.001 mg/kg/day to about 500 mg/kg/day.
 12. A use for the compound of claim 1 for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound.
 13. The use of claim 12, wherein the effective amount of the compound is in a range of from about 0.001 mg/kg/day to about 500 mg/kg/day.
 14. A use for the compound of claim 1 in the manufacture of a medicament for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the medicament.
 15. The use of claim 14, wherein the effective amount of the compound in the medicament is in a range of from about 0.001 mg/kg/day to about 500 mg/kg/day.
 16. A use for the compound of claim 1 in the preparation of a pharmaceutical composition for treating or ameliorating HD in a subject in need thereof comprising, administering to the subject an effective amount of the compound of Formula (I) or a form thereof in admixture with one or more of the pharmaceutically acceptable excipients.
 17. The use of claim 16, wherein the effective amount of the compound in the pharmaceutical composition is in a range of from about 0.001 mg/kg/day to about 500 mg/kg/day.
 18. A pharmaceutical composition comprising the compound of claim 1 in admixture with one or more pharmaceutically acceptable excipients. 